Here is a pix of my synth project. The top panel has artwork that will get applied to the panel. Lots of holes drilled...whew! Below is the bottom panel with applied artwork and holes ready for mounting controls! I spent many hours getting the artwork right. That would dictate where the holes would go and allow for spacing of the pots and switches and to get it all to fit on the panel size I had.
The electronics is a design from Elby Designs Australia. (http://www.elby-designs.com/contents/en-us/d4.html) I have the ASM2...a second generation from the ASM1 by Gene Stopp. Still a 'buttload' of work to do to get it all wired. I've added an 8 Chan. Sequencer that I will 
implement with a AVR Tiny2313 with Arduino code.