I use Astrodon LRGB filter set and Baader Ha-OIII-SII filter set ...
Astrodon filters are 49,7mm round and 3mm + - 0.025mm thick
Baader narrowband filters are 50.8mm and 3mm thick...
Even with 1,1mm of difference in diameter..both ftype of filters fits into the filterwheel hole...some screws and washers are used to fit unmounted filters of slight different sizes..
I don´t understand why this is a problem..For example..SBIG makes an only filterwheel size. The holes for filters of the filterwheel permits to screw 2" filters and also insert 49,7mm and 50.8 mm filters.
So you have ONLY 1 filterwheel valid for 50mm,50.8mm (Unmounted) and also for 2" (mounted) filters..
To fix unmounted filters in the hole they use 3 screws per hole that permits fix different filter sizes.. The 2" filters just screw in the holes..
I attach a documment to show it..
I think this is a perfect "all-valid" solution...