Adding a Flip Mirror to replace the Moonlight Focuser

I want to add a flip mirror so I can easily flip between the straight-through CCD camera as per usual, and then flipping to use a Watec 910hx video camera for occultations. This page is to see if this can be done with different flip mirror options I can find online

Vixen 2" Flip Mirror $129 from OPT

First question: Can I have the f/6.3 reducer upstream of the flip mirror so I get the image compression on both the SBIG camera and also the Watec camera? Apparently the body of the flip mirror is "a bit more than 2 inches" so that is a bit more than 51mm so maybe 54mm? Compare to the current distance from the f/6.3 lens surfact to the SBIG chip, which looks to be about 114mm. That's bigger than the supposed 105mm "back focus" for the f/6.3, but is that on an f/10 12"? Maybe that's for a smaller scope. Anyway, I clearly have good focus as the picture below shows, so it seems that the Vixen is clearly not too big to make worry about back focus

 

Teleskop Shop 2" Flip Mirror

this one has less depth and so more forgiving of backfocus needs. Perhaps also wider (2"?) hole through, than Vixen? The Watec chip is 1/3 inch = 9mm, compared to 16mm for size of prism.

worry: If I'm taking out the Moonlight, I'll get mirror shift when using the Meade primary mirror focuser for everything. I see recommendations against relying on that focuser. I can't remember why I got the Moonlight, but maybe I too was unhappy with the SCT focuser. I don't have enough backfocus to both have a flip mirror and the Moonlight and f/6.3 I believe. Maybe the whole idea is not going to work??