I finally had a chance to get back into this build. All the pieces are here. Confidence was not high - after a lot of back and forth I finally got the order in for the acrylic, but was not convinced I was going to get what I ordered. But it arrived, and was exactly as I needed!!
They even polished the edges, which I wasn't sure they were going to do - bonus. I popped everything in place, leaving the blue card underneath to avoid scratches and it looks exactly as the design - another little win, who knew powerpoint was the new CAD.
The acrylic is beautifully cut and cleaned and fits perfectly. The bolt holes are a bonus, one less thin for me to mess up. The only thin I need to do is drill the standoff holes and one big hole for the pump and the acrylic work is done.
Next job was the light troughs for the LEDs. I was hoping to make it nice and neat, but the router (my unsteady hands) was a bit wobbly. I did consider using guides, but given it is all hidden under the vinyl and the acrylic I was happy to live with it. The troughs are 1cm wide, just wider than the LEDs, and deep enough that they are below the level of the board so the acrylic sits on top of them.
Cutting the cable holes was a little trickier. Ltots of trail and error on a rough piece allowed me to work out what combination of arbor, wood drill, and jigsay worked for each of the different hole sizes. I have rubber grommets for them so it should looks nice and smart when installed - I noticed a lot of other builds just left the open holes, but I've never liked that and much prefer using cable tidies. I spend a lot of time cursing the chipboard, as it has a tendence to flake if you are over-enthusiastic going through the board. Again, not too fussed as the vinyl will cover all sins, but I did at least use some filler to level off the worst offenders and leave a smooth surface.
I put off attaching the wall mount as I was pretty sure some of the bolts for the arm and the VESA mount would be poorly placed and interfere with the PC side of the board. I marked it all up, and decided on the horizontal mounts to give it a bit more strength - it is going to be holding a lot of weight once the build is all in place! Drilling complete and it turns out that for once, I was lucky. Everything is clear and nothing interferes. One of the LED holes is hidden, but it is only the end bit that is loose anyway, so will simply tuck in nicely. I have initially set it up with 4 bolts, which should be enough, but I am seriously considering using another 4 of the holes and taking it to 8 - mostly because I can!
I'm leaving it overnight for the filler to cure, and will then repaint to cuts (I'm using a waterproof paint as it is going in the garage which is currently uninsulated, so I don't want moisture rotting the board. Frustratingly, I can almost see the finish line now. As soon as the vinyl is on I can build and mount the rig. Unfortunately, I have a mate who is a deft touch with vinyl coming to save me from myself, but he is away at the moment, so I will see if I can wait for his return, or give in and just have a go.