Alright... after staring at this thing for the better part of a week, I decided to take the leap and use the double sided tape to hold the marquee plexiglas in place. Hot glue was another consideration but I was afraid it would be too bulky once dried for the monitor to sit flush against the plexiglas so I ultimately went with the tape. I just used a little bit in the corners because the tape is strong and all it has to do is keep the plexiglas from moving and withstand a tiny amount of pressure when dusting/cleaning. It seems to have worked? I guess time will tell.
Here are shots from the back (tape is in the corners) and front:


Once the the plexiglas was in place, I was able to install the marquee monitor. This was a little tricky but not too bad. I cut out a piece of 1/4" MDF the width of the cabinet and drilled holes in the center for the Vesa mounting screws (M4 size in case anyone needs to know). I drilled these holes slightly big to allow myself some wiggle room in case things didn't exactly line up.


Once I got the monitor mounted to the MDF, I held it in place so that I could do some fine tuning. I had to make sure the ends of the MDF sat flush to the strips of wood on the sides so that I could screw it in place... but at the same time I had to make sure that the monitor was as far forward as possible so that it rests against the plexiglass. To make small adjustments, I added some washers in between the back of the monitor and the MDF - I tried a bunch of different combinations until I was satisfied with the fit. It turned out that a 1/8" rubber washer plus 1 regular washer (that couldn't have been more than 0.5mm thick) did the trick.

Once I had everything dialed in, I used 4 screws to secure the monitor in place.


So here's where I'm at with the monitor and plexiglas installed...

Now the real trick will be getting the marquee to display exactly in the area that I want... BigBox xml files can be tweaked but I'm not sure how yet. Hyperspin (with Hypermarquee) has a window that can be dragged and resized to wherever you want, which sounds perfect, but apparently Hyperspin is currently broken due to a Windows 10 update in May. No word on when that will be sorted out.
I bit the bullet and started putting in bids on computer monitors on eBay so hopefully I'll have one in hand by the end of the week. I'm a little nervous about this - hopefully whatever I get will behave like I want (power on when computer comes on). In the mean time, I'm going to begin working on designing the control panel and sorting out the artwork.
