We can look into something like this. It has always been our recommendation in the past to always focus with LRGB (even when shooting narrowband), but if gain works to reduce the exposure time, maybe? I still worry that there will be much data that is unavailable to HFR metrics engine using narrowband. In the end, the proof would be in the quality of focus. When you set gain manually to this value and run Auto Focus you are happy with the resultant focus at the end of the run?
Here is our current perspective on focus sets. It is pretty high on the priority list due to it’s popularity: