Looks good. I wouldn't mind trying my hand at building one at some stage, so parts list would be great if available.
I definitely want a higher range gauge like the one you've shown there. I'm pissing in the wind a bit when I let it get up to the area between the two screws on the KK one. I'm guessing this is about 20 psi. Seems to get me down to 10 or 12 when I cold crash so works OK, but I'd like to know for sure.
I would also like to run it using a barbed disconnect and mount both the gauge and the pressure adjustment into the collar of my ferment keezer. This was I can check and adjust from the outside without having to open it all the time.