I removed the bounce on my 30 ft. TT with 2 mods:
1. Fastway wheel chocks (to stop wheels from rolling in either direction. Put these down between your tires before you unhitch to prevent trailer from rolling away. Adjust once and just place and step to lock the wheels from rolling in either direction.

2. Extra pair of scissor jacks in middle (front of axles) to stop middle section bouncing. So now I have 3 Scissors jacks on each side of the trailer. No more bounce.

Ed