I have had mine totally apart and back together. Tiny #1 (on the side of the cell) is not holding the primary mirror in place, it simply locks the screws that do (the big #4 screws on the back) from turning once you are done.
When you say “holding the mirror”, do you mean the three screw set #4 or the set of three pairs that hold the mirror clips? #4 set of three holds the mirror cell (that includes the mirror) but not the actual mirror.
I would not remove the actual mirror (from the mirror cell/backplate) since that would mean recentering and resecuring it. Removing the mirror not only risks not centering it properly but also either pinching it or not getting it secure. One will give triangular stars and the other will let the mirror flop, changing the collimation when it does. Removing the mirror can be done but is not needed to clean the mirror, all you need to do that is to mark the backplate/mirror cell rotation relative to the tube so you know how it goes back in and then loosen the locking screws (#1) and remove the cell holding screws (#4). Then the mirror and cell will drop out (hopefully not on the floor😉).
When you put the rear cell with mirror back in you should advance the rear cell push screws just a bit first (6 of them - #2 and #3) and equally. If you don’t do that and the tips are flush, then the #4 cell holding screws (also pull screws for collimation) will have no latitude to adjust as you would be pulled tight against the back of the OTA.
I would HIGHLY suggest an OCAL to collimate. Much easier and more accurate than any Tak tools. I have used both as well as a laser and the OCAL beats everything in terms of ease and accuracy.
