I'd wait for the five amp batteries. I know a guy that used 3700 mAh 10 packs in his Integral. All was well until he flew at a competition that was really hot and windy (30+ mph winds). It turned out that day that 3700 wasn't quite enough for his routine. He puffed the pack.

You will have a 4000mAh pack, but you should only use about 3200mAh or so to retain battery longevity. With the 5A pack, you'll have 4A to use without breaking 80%.