+3 for the 400w

As for yield under 400w, I've been pulling 2.5-3 oz per plant off of my blueberry (indica dom) under the 400,... my biggest under the 400 was 3.5oz finished and cured.

I can get 2-3 plants of that size under that light. It's tight, but works ok. Check out my last grow log This was done under 400w, and for the first 3/4 of the grow there was another plant that also yielded over 3 oz in the same area!