I got to 640 today. I haven't seen numbers like that since the fall. I think in the past, when I have tried to do high volume swings, I've made the mistake of doing sets of 100 in the beginning, trying to get as many reps in as possible, but I end up wearing myself out too soon. I never timed sets or breaks, either. In any case, the 1:1 ratio is really good for me. I average about 40-42 reps per minute. I set the gymboss for 31 sets (that's including the rest time) 16 sets x 40 reps = 640. Mostly with the 18lb - I did about 3 sets with the 26lb in the beginning, but knew I'd wear out too quickly if I continued.
All in all, I'm very proud of myself. When I think of where I was a year ago in terms of endurance, it's like night and day.