LOL--I have a 4' 4 bulb T5 that puts out 20,000 lumens. I have given some thought to adding another 4' 2 bulb fixture as I am actually underlit. However, I am quite happy with my veggy growth under the current light.
There are many people who take clones from clones--I certainly was not the first to do this. In years past, we were told that there strain degradation if you took clones from clones. However, in actual practice I have not found this to be true. I have had some strains that seemed to get better. This could just me getting to know the needs of the strains better after several generations,though.
Are you going to have separate vegging and flowering spots?