help needed. can i use 400w hps for veg? etc etc..

@topic
im on a tight budget right now and i can only afford one 400w HPS set as of the moment. or should i veg them outdoors then transfer indoors?
also, can i use a MH bulb on a HPS ballast? what are the cons?
i cant grow them outdoors from flowering to harvest because i have a 6 feet limitation and and our neighbors can see our garden from the top of their apartment
still waiting for my Satori's to arrive so i can grow them together with Aurora Indica

TIA

400 hps is fine for vegging. Just expect a little more stretching than under mh, but some people say you get more bud sites from hps. If your ballast is hps only you can't run a mh bulb on it, period.

Veg with cfls, I have a 400 watt MH and almost never use it for vegging anymore. I get decent crops vegging with cfl's and then 400 hps. The Aurora kicks ass. Every Satori I tried, I've either gotten a make or killed the seed. Hope you get females. sposed to be an awesome smoke, a little long to flower, but worth the wait I hear

You can run a MH in a HPS ballast; just not the other way around (due to the igniter on the HPS).

And yes you can do the whole grow on a MH. I did my first grow this way (I don't advise it though). I didn't have a clue what I was doing. I left the light at the highest point the whole duration of the grow. Tall skinny plants, but I got 8.5 oz off of 5 plants.