The gym i currently train at only has DB's up to 125 pounds, so i use those without straps for 20+ reps towards the end of my back routine. I have always gotten great results from doing one arm rows.
The heaviest i have attempted was 160's for 12 reps with straps many years ago and i was already fatigued at that point. I have always been very strong at rowing movements. I've used the 140's for 15 reps without straps many years ago and that was quite an accomplishment.
I get a much better feel with DB's and i feel it more in my lats when i do a smooth stretch and contraction. I always do them controlled and try not to sling them around too much.