These days I'm anti DIY, fixtures are just too convenient and cheap to mess around with something that won't look, work or upgrade as good. However if you're looking for a DIY version of a sol
this is the closest thing I've seen, however it's quite limited in terms of control so if that is really important to you then the answer is obvious.
In terms of two sols being enough, not for SPS tank but should be decent for LPS and soft corals but you'll have to hang them pretty high and use 70 degree lenses. For SPS you'll probably want four installed the proper way. The nice thing with modular fixtures is you can add more later. I haven't seen a Vega over a tank before so can't really comment, a little more power there so if you can spread the light might be worth while.