The SST-20s I got from Kaidomain (FB4 tint bin) are kind of yellow at low power and not really my favorite tint at any power level, but I just got done reviewing a light that came with an XP-G2 that I think was a 5S tint bin so I’ll take it.
I’d put more emphasis on getting FA4 or FA1 tint if I was buying a bunch of SST-20s than I would on flux bin. I have a suspicion that sometimes non-green tint and the highest flux bins are incompatible, because adding more 555nm has a strong tendency to increase lm/W, being the peak of human visual sensitivity.
The peak current of FW3A won’t be 1.05A per emitter but significantly more. At higher currents the efficiency gap will be larger when comparing both LEDs at the same current.
Furthermore SST-20 actually has lower Vf than LH351D so it will draw more current. This will make the efficiency gap yet another bit larger, but it will reduce the brightness gap slightly.