considering cyan went from <20m to >150m (probably) between chapters, and gray went from 35 to 80 to ~150 in one chapter with a series of "teehee maybe I can get serious now" cliches...
at this point I'd consider 500m a conservative top estimate for them. not in a "this is what I hope for" kinda way, but in a "the writer is clearly jumping the shark to the moon" way. and after that kana will probably hit 1km just to show off
*sigh* the whole "DBZ but cocks" schtick was fun before it became as painfully repetitive & power-scaley as the real thing