Does it make much of a difference gradually increasing umol ?

As opposed to starting at about 1-200 then up to full veg strength at about 550umol rather than building from 14 days to 21 until desired veg phase is complete.

No once they are well rooted bring it on up. Don’t ever let them stretch in veg.

Not at all they love light so much ..fast and hard please ..see Bugbee on YT

good luck

I currently got 20 plus 1 day old germers under a 600w hps about an inch high
at about 3.5-4ft off the bulb, pushing like crazy
was worried ...yes but the love it...I'm checking every 30mins
so far ok