I have been toying with the idea of using 3M VHB tape just to get the initial bond and hold the widow in place which also acts as the shim to prevent excessive squeeze out to the point of having too thin of a film. My window pattern overlaps the window cutout by 1.25 inch, so I will use a narrow strip (3/8") of VHB tape. I'll strip the paper cover from the acrylic only off of the bonding surface and sand prep that surface, wipe with tack cloth and alcohol prep to clean.... then brush on a thin application of thinned 795. I believe this is a better substitute for black paint and prevents seeing the VHB tape through the acrylic after install. After that brushed on coating cures (24 hours or maybe a little more) I'll put on the VBH tape and mount the windows, using a wooden roller to firmly press them. I forgot to mention the mounting surface around the window cut-outs will be sand paper preped and cleaned with alcohol as well. With the windows firmly in place with VHB tape I'll 'caulk' in the 795 around the perimeter of the window, filling the gap but without too much squeeze out.
I think this way I'll have a consistent film thickness, less risk of the windows displacing during install, and not having clamps that could be too much pressure and squeeze out too much sealant. I will also add a similar bead on the inside of the windows. Does this sound reasonable?