Sorry for the late reply, just saw your post. I did my flowering with 3x of the soft (two on top and one large light on the side) and I kept one of my smaller 6.5k bulbs on the top as well to let it keep getting full spectrum (as opposed to vegging when I had 3x bulbs between 5.5k and 6.5k and one soft white). However I can't say for sure without seeing what you have, also, there are better people to ask, this is just an experiment I am running more than anything, to see what I can manage in extremely confined spaces (first yield was moderately potent despite being harvested a couple weeks early). Also, I am sure there are better, more experienced people to ask about all of your questions, I'm probably not the best source.
I'm not sure what to tell you about the transplant, I am forced to stunt my plants growth a bit when I use this setup because of the space restrictions (beyond what LST can help me with), which really hurts the yield (but not really the potency), and the main way I accomplish this is a smaller container (not to the points that the roots are cutting themselves off, but enough that I actually need to monitor the soil and fertilize almost every watering) I also typically use fast growing and very short strains as well.
As far as your electricity bill goes, I don't expect it to be very high if your only using CFL's. When I am on 24x7 lighting like I am now, it's perhaps a couple bucks a month at most for me.