Tri's I do after chest. I'll start off w/ 3 sets of weighted dips, then 3 sets of DB raises (1 db, 2 hands behind head), and 3 sets of a pushdown exercise. Usually about 7-10 reps per set. 9-10 total sets.
For bi's I'll do 3-4 sets of barbell curls (close and wide grip w/ camber bar), then 3-4 sets of a single arm curl, sometimes cables, sometimes db's, usually I'll do some type of hammer grip. Then I do reverse curls for forearms. Usually 8-9 total sets of bi's (excluding reverse curls) 7-10 reps per set.
I've tried lower volume training lots of times before and my body doesn't repspond well to that. I always lose size and strength when doing anything under 9 total sets, especially when lowering sets of compound exercises.