277 Stamina means she was level 277 (she is 280 now as I still make movies with her). Those levels convert directly into Stamina so I sometimes use either name for them. I was training her for a long time (she currently gets exactly 40560 per session), my next girl Pantress has 335 stamina, but can only get 41850 per session, so it will take her a long time to catch up to Ice (2.1M/1M/127k now).
Some girls get better than 70% but you need their valentines day lingerie and their extra gear that costs diamonds. You want to check the numbers to see how they add up. Some still don't get more than 70%. I count that 70% three times, once for each stat, then compare it with the sum of the gear I could wear together counting any "vs" piece triple. I know Sanshi, Ice, Dora, Frecly, Victoria, Cindy and Zoe can beat 70% but Indira can't. I have been building up Indira for some time, so it's a little irritating. You need the diamond gear though. It looks like Maggie can, but you have to be careful. She has 3 different necklaces that you can get for diamonds, but you would only want the "vs" one.