I must of gone thru 20 iterations for the instrument panel layout. Mocked-up the instrument subpanel in plywood to make sure switches are really where I want them, with rational flow and adaqute clearances. After some final adjustments drilled the subpanel. I used .65 inches between small circuit breakers. .7 inches spacing between the two 30 amp breakers. 1 inch min spacing between switches. I grouped the breakers and switches in logical groups with 1.5 inch spacing between switch groups and 1 inch spacing between circuit breaker groups. I made a minor mistake in learning that switch anti-rotation key-ways are not consistant, some are keyway up and some are down relative to down off positioin.