I only have a single head Ender 3 Pro. I just paused at layer 42, changed the filament and resumed printing. My second attempt was perfect. I had the resolution set to standard not high resolution the first time. They came out great after the change. No I think the size is slightly smaller. By maybe a 1/2 inch or so. I’m working on my own design now that will be a perfect match. I will print all the buttons with TPU filament ( black and white) so they have that rubber feel. I’m toying with the idea of designing a complete plug and play panel that I can sell to those who don’t want to build one. I’m really loving the designing and building now. The combination of MF and Arduino’s make for a nice clean build. I wouldn’t provide the MF software but can provide the configuration files. Like you said before. This building stuff is addictive. 
. I will have three complete panels when this G1000 one is done. We are leaving tomorrow for our month long camping trip off the grid so more updates when I get back.