if your worried about head room its always good to flower early.....even if you have the slightest bit of doubt....flower early!

Personally, when running new strains i like to flower them early anyways to find out the characteristics of the strain....i always take cuts of every plant and label them.....because some of those slow veggers or mutants; sometime turn out to be the best plants..

THe first run with a new strain is like a learning curve....i think its my 4 run with the purple wreck and i think ive finally found her sweet spot! sometimes the first time will be the best, but most of the time it wont! Good luck...the KK looks real interesting....and everything looks great~