I use P60 hosts and drop-ins for that purpose. Right now I have (6) solarforce hosts with newly built drop-ins that I’m comparing.
I’m searching for my favorite high CRI LED. Currently have several drop-ins with ~4000k high CRI LEDs to compare.
Check with SBFlashlights.com for closeout deals on solarforce hosts. Drop-ins can be made yourself for quite cheap. I use linear 7135 drivers so LED comparisons are done at known currents.
Making them yourself is the only way to control which LEDs and drivers you test.

The Convoy S2+ would be another great option.

Good luck and have fun! There are a lot of good LED options out there!

FB