Trailer tow advice?

[Arby]

Hello, I have a new 2017 All Terrain Canyon with the trailer tow package and am getting tongue "bounce" towing a 5' x 8' enclosed trailer weighing about 1300 lbs loaded. Checked tongue weight & was 350 plus so rearraigned cargo to get about 250 lbs weight. Seemed to help some. Son borrowed truck to pull 16 ft car trailer and had no bounce problems. I have considered using a 8" hitch extender to get trailer a little further away from bumper when backing. Make problem better or worse?
Any ideas or similar experiences?
Thanks,
Arby