First off Baron, whats your relative humidity?
if its above 70% yeah you might want to think
about a dehumidifier in the last month of flowering
to decrease your chances of moldy buds.
Other than that alot of people, including myself, would
love a high RH level during the vegative state. I only get
around 25% year round.

I've had great results with HPS compared to florescents
for cloning/veg. I believe it's all how well your cooling system
is designed, operates and provides the CFM your closet requires.
If all those topics provide you in the green results, or optimal growing
conditions, you'll have a better success, and a faster growth rate with
an hps or mh. As well as providing a noticably higher number reguarding lumens .
Good Luck

P.S.
Your ventilatoin idea is great, and on the right track.