about 3 in a half or 4 inch
If You have the space to do, I would pot em on, maybe straight into some idk 10L pots or so, and because of the amount of Nutes they have been getting would probably use seedling compost(gently on the Nutes) and mix a helluva lot of Perlite in, maybe 60% compost and 40% Perlite(or 70/30) after Potting-On I would only give em Water(pH'd to 6.5..use Jiffy Lemon. this is IF your water ain't so good) If you don't have a pH pen then even a cheap one from FleaBay is better than none..just make sure to get one with the calibration powder. OR plump for an Essentials pH pen(bout £30-40) above all lay off adding any nutes! give them time to recover and get used to new home, Growth WILL be slow to begin with,but don't worry they just finding their feet so to speak. Do You have Fans Blowing across them? Air circulation is a must..again FleaBay.. 6" clip on fan.. less than a tenner.
If You worrying about Height..Don't..let em recover then TOP or F.I.M or Suppercrop, hell IF you have the Time You could even ScroG them...
Lots of Choices and Paths You can still choose...just lay off the Nutes and give em more breathing space(Pot) if possible...also try and get 1 bulb per plant of decent wattage...say 50 - 80w each..hang Horizontally about 2 inches above...check Temps and Relax
atb
Nearly forgot, When(IF) You Pot-On give a good watering in..say 500ml to 1L and then DON'T water for maybe 5 days..unless soil is really dry: Use your little finger and insert into soil at the edge of the Pot down to between 1st and 2nd knuckle...if finger comes up with bits of Soil/Perlite stuck to it don't water..IF finger comes up CLEAN...Water...say every 3rd day after the 1st 5days to a week of NO water after Potting-On and Watering in..
atb
and Good Luck!!