Just thought I'd check in a few months later to show that this ended up a great guitar that gets played a lot. Not something that gets hidden in the back of the cupboard
After a few months settling in I noticed why the guitar had tuned up a bit weirdly a few times. The plate on the tailpiece had bent! While the original looked nice, the thin sheet metal just didn't have the strength to hold against a set of 12-54 strings!
So off with that and on with a more sturdy and traditional tail piece. Did this at the same time as a few tweaks and fixes to the set up and electronics. Even more happy now. Sounds great and huge fun to play unplugged. Plugged in takes it to another level, those Tonerider pickups certainly rival the Gibson originals. Definately a few things I'd do differently build wise if I did it all again, but I'm settled for the time being.
Hell, the thought of selling my long term Gibson ES-335 has passed my mind several times. Hard to keep $3.5k parked in the cupboard when my custom $500 is doing the job so well.