firstly, im no expert
....but i have one these mini homeboxes. it's not my mainbox, been using it for pre-veg type of situation. i've been able to run 50w mini ufo led (don't know it's true power draw from the wall) with decent temps with just passive air exchange and if i were you i'd go for led instead of cfl. but for cfl i'd go around 50 watts max tempwise.
im a soil guy but for this i'd use coco if i were to flower something in there. also my tent doesn't have any filtering and blooming plants will smell. sorry can't help ya with carbon filters of this size. hopefully somebody who knows something chimes in.
here's just some pics of it. first with the miniufo and tape roll.
https://www.icmag.com/ic/picture.php?albumid=50566&pictureid=1201958View Image
some cuts i had in there under 23w cfl.
https://www.icmag.com/ic/picture.php?albumid=50566&pictureid=1316531View Image
as for plant count, i'd would either go with 4 plant super micro sog or one "big" horizontally trained plant. i'd estimate depending on your micro mastery skills you could hit 0-1 oz of yield.
i didn't flower them under it. as is said i've only used it for vegging so far.
With good ventilation it is no problem, I would even go higher due to the short range of effective cfl light. And since you seem like a beginner I'd recommend 2-4 plants under there so there is more buffer room for mistakes.Can i put 2x 40w CFL or i will have problems with temperature ???
My frend grows home box 30x30x60 tent. Light is 100w led now and last grows light is 120w led. Current grow is just start but last grow he harvest on one plants +/- 45g. Strain is th seeds af bubblegums.