Robin:
Watching the video of you loading your TI on your trailer looked absolutely painful, just sayin.
Most of us have switched over to PVC bunks now, way easier to get the boat on the trailer. ( those cradles scratch the crap out of your boat, if you live in a sandy area, and the boat is really hard to pull over them (thats that sqeeking noise in your video, (your TI getting scratched to smitherines (lol)) Since you already have the front cradle, just keep that in there, If it was me I would remove the rear cradle and replace with two 1 1/2dia PVC pipes (or whatever size pvc wooden broom handles fit inside easily), mounted on 11-12 inch centers. Have the pipes stick out behind the back of the trailer a foot or so, then mount a small roller to the back of the trailer in the center (I just used a 9 inch paint roller slid over some PVC pipe (the roller cost a dollar to make, the PVC pipes cost ten bucks. I takes about an hour to install everything. I went to harbor freight and got a cheap boat winch (the type with the one inch wide nylon strap (not the one with the steel cable), I think it was about $25 bucks. On mine I just replaced the cable with a 1" wide nylon cargo strap, came with a hook on the end)
My trailer is very similar to yours, what I do is back up to the waters edge (not in the water). I lift the boat up onto the roller in the back, ( the trailer automatically tilts, I only need to place my foot on it, most of the time I only need to lift the bow a couple inches at the most, in fresh water and steeper boat ramps I back in a little further and don't have to lift any thing at all, the back of the trailer dips under water with your foot on it), I already have the winch strap extended out so I can clip it to the bow. If you have a side wind the PVC pipes sticking out the back keep the boat aligned straight so you dont have to worry if the boat is straight or not. If you put bungies on yout trailer tilt mechanism, that becomes completely automatic, just place your foot on it when lifting the boat, it automatically tilts down so you only have to lift the boat a couple inches (just a suggestion). Don't worry about it if the boat drifts to one side or another, the PVC pipes sticking out the back align the boat for you automatically. I just leave my AMA's out and all my masts and sails in (keeps them from getting dunked (a bad thing).
I then just mozy up to the boat winch and crank the boat up onto the trailer (the boat doesn't have to be perfectly straight). It just doesn't matter how steep the boat ramp is. Once the boat is up on the trailer I then drive the car away from the water (not clamped down or anything, just held by the winch) into a clear area on level ground (of course watch for overhead power lines and trees. Most of the boat ramps around here have a water hose hookup so you can rinse the boat and engines off (you have to bring your own hose though). If the parking lot is bumpy I might put one strap on the boat quickly to keep the boat from tipping if it's windy (with the masts still up) but I usually don't bother).
I then just pull the car into an open level area and break the boat down, drop the masts, unhook the tramps and roll them up, then fold the AMA's in and strap everything down for road transport.
I built pretty heavy duty spray skirts from pretty heavy material so they don't get shreaded on the highway (I have shreaded 3-4 sets of spray skirts on the highway BTW), all my lines sails and rigging is trapped under the spray skirts that are wrapped and strapped over the bow (protecting everything from the road wind).
There are a ton of TI's around here, and some of the guys even have Cheap Harbor freight electric winches on their trailers (I think the cheap ones are under a hundred bucks). The trick with the electric winches is to get one that releases the spool so you can just pull the strap out instead of having to wait for the electric winch to pay out the line (electric winches are typically painfully slow).
It typically takes me about a minute at the ramp to launch or retrieve my TI. At a busy public ramp I usualy rig the boat in the parking lot in an open area, then back up to the launch (way easier because you can see your sail and AMA's in your rearview mirror. I keep one strap in place so the boat doesn't tip on the trailer.
On the bungy for your tilt mechanism, just get a couple 4 ft bungys clip then somehow to the outer edges of the trailer, in the center they run under the main frame of the trailer, just add as many bungys as it takes so it tilts down when you place your foot on it, but with enough force so the bow lifts up a little when you take your foot off.
BTW don't let go of the boat when launching because it self launches once you give it an initial shove and can drift away (guilty).
I've been running PVC cradles for 3-4 yrs now with no damage or deformation to the bottom of the boat, we store our TI in our hot Florida garage (it gets 130 degrees in there all year round during the day).
Actually I just did my annual inspection of my hull bottom yesterday (yea I only flip the boat and clean the bottom up just once a year), I'm happy to report there was no damage, so I cleaned the bottom up and sprayed on a new coat of rustolium neverwet, and I'm good to go for another year.
Hope this helps
FE
Edit: If you use neverwet its best to clean up the bottom with alcohol or heptane (heptane is rubber cement solvent, and it softens and melts polyethylene. I then put on a relly thin coat of Krylon plastic UV clear coat (the active ingredeant is heptane so it sticks nicely to polyethylene). If there are scratches in the hull the clear coat helps smooth them over. I then apply step one of neverwet (a thin coat) followed by a thin coat of step 2 (it takes about a half a can of each, so one can of step one and one of step 2 lasts for two tratments (2 yrs, I think the stuff was ten bucks). The stuff lasts about a year, but in high wear areas (like sand beaches) it scratches away eventually (who cares it's clear lol).
edit:
Here is a pic of the back of my TI, you can see the PVC pipes sticking out the back with the broom handles stuffed in (wood broom handles are really really strong when contained in PVC, and don't rot (BTW). Yould can also see my cheepo roller at the back of the trailer, it's just a cheap 9" wide paint roller slid over a piece of PVC pipe (I think it cost a buck, and 20 minutes to make (been on there 3 yrs now ( who knew it would last so long lol))). My trailer is flexible like yours, I just step on the back to tilt it down with my foot when loading.
Here is a pic of that Rustolium neverwet stuff I described (got it at Home Depot, I think it was about 15 bucks). I just just spray the boat bottom, rudder, and the props with it, it reduces water surface friction like 99%. Gotta love technology....
This is the stuff
http://www.homedepot.com/p/Rust-Oleum-N ... lsrc=aw.dsOf course you can do as you please, I'm just describing some crap that seems to make my life (and my really bad back) a little easier for me (I'm pretty darn old and frey). We are on our third TI now over the last 6 yrs, and are out on new adventures with ours pretty much weekly and love every minute of it.