Welcome MMM,
I'm sure you will enjoy the Oasis just as much as we have!
There are many posts on the carts available and a search would yield some useful info.
Recently Pirate posted a novel solution to reduce the buoyancy of the Trax cart by partially filling the tyres with water.
I have had the Trax cart for about a year now. I have swapped the balloon tyres for the Hobie heavy duty pneumatic tyres and that combination works well for me. I don't have to stay dry though and only insert/remove the cart when in knee deep water.
Pretty much twice weekly in the last two years I have launched from a dock and have had no problems getting on either the Oasis or Adventure.
I wheel the kayak to the dock edge then push from the stern until the drive clears the dock, then pick up the stern so the cart drops out. A line attached to the cart allows me to pull it out of the way. With the kayak resting on the dock with the bow in the water I fit the cart to the rear storage deck and then slide the kayak in lifting the stern so that the rudder clears the dock . A stern rope through the rear padeye helps keep control. The Adventure is easier to launch because the cart sits well back but I did launch the Oasis this way for over a year before I got the Adventure.