I would also load the TV as you normally would for a trip. The weight reward of the TV rear axle will make a difference in how the truck sits and I think it gets calculated into the tongue and hitch weight formula.
Correct me if im wrong.
Start out with a level trailer. I measured the bottom of the TT frame to the ground, front and rear. When I did my trailers, my loaded trucks ball was about 1" higher than the inside of my coupler. Right or wrong, it worked, it tows fine. Hitched up, truck sits level and the TT sits level maybe even very slightly lower.