how is this?

[Rtsbasic]

Thing is matched batteries give you only a small bit more punch, but they keep giving it till the battery gets very close to dumping, unmatched cells will start to drop off eariler. I notice this in the last couple of laps racing my truck (GP3300 cells).

Unless you discharge/equalise your cells after every couple of runs they'll be unmatched by the time you've used them 50 times, bear that in mind.