ImNewHere

Okay, sounds good to me. The retaining ring on mine is about 5mm from touching the mirror so there is no downward pressure, and it has a 5.75 inch ID so should catch the mirror if by some odd reason it were to come loose, though the silicone seems to be holding it well.

Yep, that was what I am referring to. That makes me feel better. So did you put that in on the bottom of the ring where it is open and have it just touching the edges of the mirror?

Thanks for this guide here. I did all this, but there is a good 5mm between my mirror and the retaining ring now. Also the retaining ring on mine sticks over the edges of the turn down by about 5mm all around, but then again I do have the first one that was released in the US. On collimating mine I found the mirror flopping thing, which is why this was valuable for me. I used automotive gasket maker silicone for water pump housings due to it being non corrosive and having good expansion and stability properties with heating and cooling. My big question is, should I be concerned about that 5mm space between the retaining ring and the mirror? If so what would you recommend for me to make the space up?