1 oz of 8's ....at around 1200 - 1225 fps ....is plenty for Trap targets from the 16 - 20 yd line...with a Modified choke.
I don't shoot a lot of Trap ...but even with bio-degradeable targets(which are crummy, I agree !! )...as long as my scores stay between 92-96 out of 100, on 16 yd singles.... I'm happy with my load of 1oz 8's....( its not the shell, that cost me 4 - 8 targets ....its me !! )...
From the 16 - 20 yd line....I stay with the same shell and a Mod choke.
For 21-25 I stay with same shell ...and go to an Imp Mod choke.
At 26 and 27 yds ( and I have not earned my right to shoot from there by registered targets )...I go to a Full choke and still 1 oz ..but I do load 7.5's instead of 8's...( but when I go back beyond the 22 yd line or so, I let the game get into my head...and my scores suffer - but its not the shells...its lack of confidence - and practice ! )....
in my opinon.....