Happy TokerDaze Beateo......i hope all is well with you today my brother.....your hps will dry the pots out quicker....not only from the heat, but also they are growing quicker than with cfl and will uptake more due to the better growth....as far as the clones go i think the 90% is if you are not using a cloner of sorts.....what i mean is from my personal experience as long as the lower stem is staying wet then my clones are fine....even when the humidity was around 20% for a couple of weeks......if you are using a tray with a dome then it is necessary to have high humidity for sure.......hope this helps out bro