Good post from Montague.. just tried the tri stretch you mentioned and it works very good.. with straps i have just started to use them in one arm Dumbbell rows. i have small hands for a man and i find now gripping the Bell very hard on my last reps.
A lot of trainers recommend NOT using straps until your last/heaviest sets, but I say make no blanket statements about training.
If your goal is functional strength/performance, then I'd agree with the first recommendation.
But, if you train purely for aesthetics/hypertrophy, then I believe in "feeling" the specific muscle(s) work more than anything - straps allow this.