Transitioning from metal halide to cxb3590 on seedlings, too stressful?

Transitioning from metal halide to cxb3590 on seedlings, too stressful? also what would be a good distance to plants if its not too stressful, running 5 cobs at 45 watts in a 3 by 3 area.

thats 25W/ SF, 18-24" should be fine to start, 12-18" once they get going

Thanks!