Thanks! That means a lot since after I uploaded my observation to the AAVSO, another person uploaded theirs and placed the supernova nearly a full magnitude fainter just half an hour before my observation. I know what I saw, just don't know what they saw...
So, are you saying that you felt the supernova was magnitude +12.2 on Saturday evening when you looked at it? And on Sunday evening you felt the supernova was magnitude +11.2? Interesting how your estimates are always about 0.3 fainter than mine. Well, at least we're consistent!
Any way around this? Assuming the SN is more like +0.3 B-V (blue in photographs it seems), I would normally think I need to keep the comparison stars just as close.
I estimated 11.1 last night, 12.2 the night before. Your estimates for this one have been on the bright side of the visual range from what I saw in AAVSO and the photometric measurements, but different observers see these things differently and that is why they want multiple observers. I can't check this now as AAVSO can't be reached.
With respect to smoke dimming. The only way I can see around it is getting away from the smoke, not taking measurements when there is any substantial amount of smoke. As Robin notes, this is a very hot source, so the B-V is negative (e.g. -0.2). The comparison stars have primarily been in the +0.5 range.
I don't have a good feel for how much relative shift there might be for different stars with different levels of smoke dimming, but the absorption is stronger in the blue. Smoke opacity tends to vary throughout a session, sometimes by several magnitudes, so it would be tough to come up with a scale for this, especially since the SN and stars have their own differing characteristic emission curves. I can say that wildfire smoke made an excellent red filter for Mars.