how to get most height out of clones

So i have about 30 clones that have been out of the humidity dome and in soil for about 5 days. They are going to be finished outdoors. Just wanted to get opinions on how to get them the tallest, by that i mean will they gain more height under 24/7 MH light or will they get taller outside? I am in central IL if that helps. and we are getting about 15hrs of daylight right now.

Hps bulb and raise the light as high as possible and they will stretch. Outdoor would work to but you need to harden them off.

My clones grow much better and faster outdoors.. They love the sun and fresh air.. I've used 600 hps and 400 cmh lights indoors and there is no comparison..

if you can harden them off, i would leave them outside.

I'm sure they will get bigger outdoors vs. the MH light

outside is the best way to go good luck growon!