First grow on rockwool

Large cubes would root just as fast just need to change watering quantities/intervals takes longer to dry back than smaller. Try watering seedlings in Large blocks starting with ebb n flo just ensure your water is being wicked high enough to touch continue until ready to flip then drain to waste. Or if you have the ability to control how much plant Is receiving thru your floraflex try crop steering, if you don't have something like a trolmaster aqua, a digital timer with atleast 8x/24hr and can be controlled down to seconds and some basic math you'll see explosives growth all around like uve never seen before, cutting days to weeks off complete cycle!