Ok I hear your optimisim, not long ago I knew of somebody just like this, namely myself. I was a dreamer, counting my cash, thinking big.
Number one, that kind of operation takes a shit pot of labor
Number two, you have screwed up allready by posting your intentions of such a large grow, your best bet is to stop now or face being busted.
Number three, try growing a few plants first so you can fiqure out the work load and fine tune your abilities.
Number four, even if you were able to grow 250 plants, how are you going to harvest and cure that many without a large work force.
I have been there and learned and I only tell you this so you do not make the same mistakes I did.
Just grow a few for yourself and save yourself alot of headaches and financial stress.
If things go good then you may consider increasing, but I doubt you will.
Good Luck
plantvision