Oh I know That's its very easy to outperform CFL with Mh/Hps...Don't know about Green Thumb...been lucky I think and just read loads and watch loads of videos..Grew up on a Farm, but was Animals not Plants...IDK? Had 1 x of Hermie All time I've been Growing...Met a Few Good folk's on R.I.U. and Learned from them too.
I still use a Mh/Hps in one Grow Setup, But only 250w at the moment, Had moved up to 600w but killed the Leccy Bill(UK) saving @ the moment for a Digital Dimmable Ballast, maybe 400w IDK? got save some more pennies first..._ I do know I have better Results with Vertical over Horizontally Hung, with Gals Sat around the Bulb...Always a better Yield for Me this way...
atb