You can obsess over this until the cows come home.
Fact is, a year from now (hell, a MONTH from now) there'll be some newfangled do-dad that you'll just HAVE to have (don't ask me how I know....).
Best to make everything flexible - you'll NEVER nail it on the first try.
Make an overall panel that is easy to replace and put whatever cutouts you need TODAY. Make a thin, easy to work with, good-looking, starboard, lexan, or delrin back- or sub-panel with easy to drill circle cutouts that fit whatever you have right now.
When the newfangled do-dad comes out, just cut a new, easy-to-cut sub-panel with the 3.128769263" hole sizes and swap it out wholesale - and your good to go!

Relax!
A low-cost re-do is much less stressful that doing it right the first time!

JMHO,
Ray