Awesome work, as always. I have a huge appreciation for your attention to detail. I know the level of patience it takes to spend hours on the details that don't actually lend to functionality.
I never see it in pictures, but I assume you have some form of shop you do your work in? I can't imagine you are painting and routing in your living room...
The reason I ask is because I see some of your painted finishes you are using a flat black paint and then varnishing. I would suggest looking into either catalyzed varnish or catalyzed lacquer. I have been using catalyzed lacquer for years and if you have a regular shop setup, a decent HVLP sprayer is not all that expensive, the lacquer lasts for a few months in the gun so the only cleanup is when your project is finished, and the drying times are measured in minutes, not hours or days. I would shoot a quick coat on a project, wait 20 minutes, come back out and hit it with some steel wool, then wipe it down with cheesecloth, hit it with a second coat, wait another 20-30 minutes, and repeat one final time. Depending on the finish (flat, satin, semi, or gloss) I might hit it one last time after a few hours of curing with some 0000 steel wool just to get rid of any fuzzy stuff that got in the lacquer while it was drying (if semi or gloss, just scrub it a little with a microfiber cloth). The finish ends up super strong, goes on FAST, and is ready for assembly in hours if you want to be careful, less than a full day if you need to handle it a lot. Far better than any brush on finish.
And you can lacquer in colors too. High Gloss Black Lacquer gives you an amazing finish, with drying times that are a fraction of a rattle can and none of the brush marks of a brush on varnish finish. The only problem with the high gloss is that until it is fully cured it is easy to mar the glossy finish, and any poorly prepared piece will show the flaws.
OH, and I would try textured ABS for the cover .. the 1/16th stuff is fairly easy to cut with a knife, and the textured surface would lend itself to your other finishes.
Keep up the good work, I enjoy watching your builds.