When I converted one to a single I just modified standard 16mm MCPCBs. No aux so a custom-designed one would be ideal. I made an aux “ring” though. In case anyone missed it here it is:
I modded a 5050 board but didn’t try a SFT40 (the couple I have are nasty green). I think I tried a Yinding 3000k but I’m a tint snob and didn’t care for it.
I also tried a 3030 board with a W2 (I figured too much current for a W1). I didn’t like it with the Convoy T2 reflector I was using.
The reflector/optic will be a limitation with a single. The stock bezel is quite shallow. You can use a T2/T3 bezel (or Sofirn SP10) for more depth but still limited options.
I’m working on a custom bezel made out of a brass plumbing fitting but it’s slow progess with my limited time (also waiting on more reflector/TIRs to arrive before I do more machining).