Remy (the guy in the pink helmet) helped me out with the same question. Thanks Remy

I took off those 2 top bars.
Bought 2x3" white PVC pipes (I did not want black because black gets hotter). smooth out the ends.
1 foot of 2x5
4 metal pipe clamps
The 2x4 went on the back railing so the 3" PVC end would sit on it. If the 2x4 was not there the pipe would not provide enough height to keep the PA off of the trailer.
I drilled holes about 6" apart and then used them to clamp the PVC on. I also threw string in there in case the clamp broke. Even if the camp does break the uprights on the Malone will keep the PA from falling off the side. The clamps allow the PVC to flex, don't tighten them until the PA is on the trailer.
If you have a non-retractable tongue then fix an upright to secure the bow to it. If your tongue is retractable then you must secure the back and front with long tie downs (not on the handles). I use 2 more tie downs in the middle.
I may put carpet on mine.
With this setup the PA can also be launched right from the trailer.
I really don't know why anyone would keep those 2 top bars on the trailer. If more cargo space is needed add a 2nd level like Remy.
finny.
PS. If your trailer does not appear square call the Malone guys and they will give you a trick to quickly true it up.