definitely need to avoid pissing off the wife!4 plants work in a 5x5. Tight but manageable. I think a 5x5 and 2 of Mars new SP3000 (i think that is the model #) would be an ideal setup. So $1k. LOL but you can probably get 200 bucks for your current light and tent. Pissing off the wife is not a good idea. Not worth it. Better to buy bud and stay married.
Growing not a full time occupation, I do hope it to become just an occasional grow (once every 8-12 months!)
I need to add another small tent for drying, and I _might_ be able to repurpose the new small tent to a secondary grow tent up until the big girls are ready to harvest, and then move the smaller ones back to the current grow tent.