I have one good size area to work with - 6'W x 8'.5"L x 6'.5"H. In that space I'll put a tent 2' x 4' x 6' or something around those dimensions for veg and mothers.

SCROG - Screen of Green. It is a form of training. You place a screen over the plant then train the plant to grow under the screen. This forces the branches apart exposing underside bud sites and leaves to light. Light reaches more of the plant so all of your bud sites produce better yields. This guy has a very nice implementation. Note that his implementation is curved upward due to space issues. Traditionally the screen sits flat above the plant anywhere from 8 - 12 inches over the seedling. The higher up the screen, the longer you must veg it as the plant needs to reach the screen before you start flower, or rather, you aim for the plant to cover 60% - 70% of the screen before flower. Again, strain dependent. A stavia will require more room to stretch so you would not want to fill as much screen before flower.

3oz / plant seems a little on the high side unless you plant to grow them to 4 or 5 feet. I could be wrong and of course, strain has a lot to do with this calculation.