So far all I have is a wood cabinet - 23" x 21" x 40" (58 x 52 x 100cm). White interior. The plan is pretty standard: - only 1 or 2 plants in fabric pots - one or two small oscillating fans (6" or 15cm) - 250W HPS 2100K 32000lm bulb - 250W dimmable ballast - air cooled reflector - exhaust fan (about 200 m3/h or ~120 cfm) - carbon filter (rating slightly higher than the fan) - passive intake hole(s) at the bottom of the cabinet - no outdoor venting if I can avoid it (would be too compromising, couldn't mask it well enough) - bare minimum ducting I've done my research, but I still have a few questions: 1) if the cabinet's width is 23", it's a bit too narrow to fit the filter (7"-10" or 18-25cm), the air cooled reflector (17"-21" or 44-52cm) and the exhaust fan in a straight line. Can I just do this? ...which leads me to the next question... 2) should I bother trying to fit it all inside a cabinet of this size *OR* should I get something slightly bigger just to avoid future hassle (plant too close to bulb etc.)? the biggest I can go without attracting attention is about 28" x 28" x 47" (70 x 70 x 120cm). 3) (see picture below) the first one is $35 and the second one is $90. Is there a noticable difference in efficiency? Again, I'm on a preeeetty tight budget. 4) is the 250W HPS the only bulb I need? I read somewhere that a CFL bulb might be good for germination/sprouting and I'm not sure if it's true.