In case it matters,,I am using a 12 inch dob and imaging with a cell phone..
A dob and a filter slide are great together. Something I hadn't considered when buying was focal shift when going from one filter to the next. My Lumicons (UHC, OIII, H-beta) are all parfocal, and my Astronomiks (642, 6/12 nm h-alpha) are parfocal, but not with the Baader UHC or each other. It depends mostly on the thickness of the glass used to make the filter. Sticking to one company may increase your chances of parfocal, but there is no guarantee.
Avoid the UHCs with h-alpha as well if you will be imaging. The h-alpha does very little visually anyway, except on stars. You won't be let down with any of the high transmission narrow band filters. Availability may be your biggest costraint right now.