I had shipped my blank instrument panel up to SteinAir in Minnesota a couple of weeks ago to have them cut out the avionics on their CNC machine. It had arrived back this week and I had forgot to blog about it. They have all the avionics dimensions saved and can configure your panel any way you want. The benefit to having them cut out all the holes is that they also cut all the screw and rivet holes. My configuration has the two radios, intercom and autopilot panel very close to each other. There are four nutplates for each off them which means there are a lot of holes. I cleaned up all the edges and holes before countersinking for the rivets. After that work was done I temporarily screwed it in place. This will now give me the correct placement and length of the harnesses I will build.
So the idea is that after I have all the harnesses built and I buy the avionics I will be able to screw them in place and attach the harnesses and I will be good to go.