I've spent about half that.... $5k so far on my setup in total including everything and I'm not even done. You can keep spending money forever.
If I had another 5k I'd upgrade the veg rack lights, add C02, upgrade one of my 1,000watt reflectors, maybe upgrade to digi ballasts, add 2 light movers (i plan to do this soon) etc..
40 in flower at a time. Just finishing up a batch of 16 five gallon pots, but starting next round we will do 40 a time in smaller pots.
