1# = know what your doin be4 you start.. cut the peices to the right size ...
2# = make it lightproof ... light will come out between the cracks of peices nailed or screwed together.
3# = DOORs Are a BITCH

put a lock on it and make sure its lightproof
4# = paint inside white and put hangers on the top to hold your light cords/strings
5# = venting and odor control. cut 3 holes 2 exaust 1 intake put some tubing up and rig it to a carbon filter ( ozone generator carbon sock types of gels also work for odor elimination) you prolly wont need vent in clone/mother area cuz they wont stink and they like humidity so you prolly wont need ventalation
6# = you have enought power just make sure your amp's dont exceed your breakers limit..... it shouldent unless you have like 6 big screen tv's on the same part of the house
7# = heat will be an issue... try to make the cabinet as tall as possible. 4 ft might not be optimal for HID lighting . 10 inches for pot. 7 for lighting and 8-12 for space between lights and your alredi down a foot or 2 so your left with only 2 ft for the actual plant. so make it as big as you can