With 2 TSL 2000s, your plants should be about 26" away would be my estimate (hard to calculate for 2 lights). Any closer will stunt them. Any higher will cause stretching, which is no good either. Seems like a good idea, you want nice tall plants. The plants, however, need to work on things other than height. You don't want them redirecting energy to be tall and lanky.
It's definitely time to get them put of the solo cups though. They are probably rootbpund right now, which will cause all sorts of issues.