Re filters etc, I have a Leupold honeycomb sunshade which when employed with my 40x Comp actually improves range finding.
I just need a Butler Creek flip up then I'm going to trial it during the coming months.
@rob, As the eyes contains the only iris in the equation the transition lenses tend to keep it at a constant aperture taking that factor out.
So reducing the error.
Less is more.
More or less.