I understand the frustration. It's exactly what happened on my 45 before I added the t5s. When they become mini colonies, they started shading themselves, and the others. One big problem with Radions is you will need more than you think enough. The coverage in their advertising is a joke. If you want to grow some serious sps, don't rely on their numbers, just go with as much as you can put above the tank! I have a xr15 pro on my 5 gallons frag tank, and I feel it just enough to hold them as frags, nowhere near "growing sps". I have another xr15 pro in my ... 2.5 gallons grow out tank and it JUST enough to grow my mini colonies. So in your tank, I think you should have 3 instead of 2 radions.
But like you said, this system is a great opportunity for me to test out those G4s pro. They are said to be as good coverage as t5s.
My lights are About 12" above the water. Enough or not enough also depend on your sps placement (middle only or spread to the sides too, high or low), the deep of your tank....
In my experience, I succeed with 2 g3 pro and 4t5s on my 38 inch long, sps grow from side to side, from bottom glass to the overflow box.
Again, put as much as light as you can. You can always dial down the intensity.