I am running 2 kessils and a Giesemann Spectra (one bulb, 4 T5s) and I absolutely love it. I run the Kessils on the outside of the Spectra angled in but when all three shimmer lights are on its simple an amazing combo of shimmer color etc. But it makes the top of my tank a bit messy
I love Radium Lit tanks, but my temps were getting pretty high in the Texas summers while running 2x250w. I also found the hotspots to be hard to work with in coral placement. That is the reason I went Orphek over Radion, as the par is a nice even spread similar to t5