70 grams every 5 weeks? probably not going to happen the average grow cycle takes about 9 weeks. but if you pack 4 plants into your flower room you could easily end up with about 100 grams every 9 weeks. then you have to dry it, which can take anywhere from 3 days to 3 weeks.

flouro's will work just fine for mother and clone room.
i would only make the clone room about 16 inches, enough room for flouro's then about 1 foot of growing room

with the ventilation i would personally instal a squirell fan. they push alot of air fast, then i would hook up a small carbon filter for the smell. you wouldn't need anything to cool down the hps directly. just make sure that there is sufficient airflow through there. check the cfm rating on your fan and make sure there is new air in there every 5 minutes and you should be fine