ok..take what you want from this..
for the price you are crazy not to go with the 400w digital mh/hps. you will figure a way to vent the room im sure. environment is the key to a good grow..you know this. in flower you are going to have to do something about the smell and venting into the attic is a good way to mask this (hint,hint to roomie) one 4" hole is very easy to fix..put the cut piece back when finished..hole fixed. so that is that on the ventilation.
as far as the cutting away pot, why?? cant you just remove it like you said? the new pot idea and fresh soil sounds great and your plant will love the FF. here is what i do when potting..stones and lava rocks are great for keeping the soil and roots getting air from the bottom. i have found what works for me is to use styrofoam packing material (the
S shaped). make sure it is not the green or pink coated..i think these are made from some sort of rice filler and will break down when wet. the white styrofoam will not breakdown. this may sound silly, but take a piece and chew on it..if it melts in your mouth no good. i use about a two inch layer in the bottom of each pot. i never have a problem with root rot or over watering. after harvest i empty the pots and recycle the (
S) for the next pot. hope this all makes sense and you can use some of this to benefit from in the future.
i used to make my perlite from this also in a food processor..ill have to find the link ..brb...here is the link..
Perlite...using Styrofoam Packing Material forgot to add that there is a cut and paste in the thread about using the styrofoam in the pots.