Vf effect on runtime and brightness.

I'm having a bit of a debate going on with myself about whether to use a TYOH, or TYOK in a mod that I'm planning to do next week.
Seems like I've read the the K Vf might be brighter for some reason?
I know the H will run longer, but how much longer?
Or is there enough difference for it to matter one way or the other?
btw, the set-up will be 1 Pila 168S, or 1xR123 in Longbow Micra and Mini bodies with either IMS 17mm reflector in stock head, or a PR head, using a Wizard 937 if that matters.
Since I'm using rechargeables, maximum brightness will win out over runtime, unless it's a significant difference.
Please share your thoughts.
Thank you

H bin=3.03V-3.27V=3.15V average
K bin=3.51V-3.75V=3.63V average
So a difference in voltage of .48 volts
That would be 15% less runtime on average, so for 100 minutes, that would be 15 minutes less.

Also consider the Vf of an LumiLEDs Luxeon emitter/star typically drops around 0.3V after 100 hours of operation.

Talk to evan9162 on the details, or search here on cpf.