I would start with the two A500x and if you feel you need more coverage add a third a500x. They have a very wide spread at 130 degrees. Much wider than older Kessil lights. Be careful how much you weigh advice from people recommending T5, especially those that don't own an a500x. There is a strong bias here towards diffuse even lighting. It's the trend in the hobby right now, and it's why T5 is so often recommended. There is nothing wrong with T5 if you like it, but it looks nothing like a Kessil. It's soft, diffuse, and in my opinion looks "dead". I feel Radion looks the same way. It all depends on what you like, but if you like Kessil you aren't going to like T5.
I started with T5 over a decade ago and despised it from the beginning. It's soft, lights everything with no natural shadows, and to me looks "blah". It's the grocery store lighting of aquariums. I switched to metal halide, which I loved. It sparkles and shimmers like the sun. Reminds me of diving a reef mid day. Now I have a Kessil a500x and it comes the closest to MH. No other light looks alive to my eyes other than Kessil and MH. If I had to choose an LED panel, I would go with the Reefi uno 2 pro. It's stronger than the XR30 by a large margin, has a better shimmer, and is half the price. With the Reefi out there, you're only buying a radion for it's name. But I would personally stick with kessil.
All that said, if you like Kessil, stick with Kessil. Nothing else will give you that shimmer other than metal halide. T5 is the farthest away you'll get from shimmer. The a500x is a beast of a light. Two will probably do you just fine, and you can always add a third later if you need it.
