Mirror update:
Sacrificing the mirror was a success!!
Turns out I still had the clear layer on BOTH mirrors!! I suspected as much as the beam was not very focused in the few tests I did on the glow paper.

Here's how to properly prep the mirrors during your build.

START with the mirrors. Really, step one.
Use a flat head jeweller's screw driver to scratch at the end of the NARROW part of the mirror.
The blue layer will come off with out too much trouble but the clear layer will need more effort.
If the clear layer is still on, scratching it with the screw driver will feel a little soft. You will notice a slightly rubbery tactile response (of course the mirror itself isn't exactly "hard"). You might start to see the clear layer start to stretch and distort before it peals off.
Once the layers peal back ***DO NOT REMOVE THEM YET *** !!!
FULLY removing the protective films will be done near the end of the printer build so the mirrors stay protected. With the the layers already propelled, you will have a MUCH easier time doing the final removal when the time comes.

Lucky for me, the scratches I put in one of my mirror was only a scratch in the clear layer !! All mirrors look shiny and new :-)

Jason