If doing a panel upgrade and needing to fill some “steam gauge” holes, you might find these useful:
Blanking plates for 2-1/4” and 3-1/8” diameter aircraft instrument panel holes.
Download FOC from cults3d.com and print in PLA+ or PA-CF. I think they look a bit smarter than the usual scraps of aluminium sheet.
That looks really good, although if I had a spare hole I would put an engine monitor or a fuel totaliser in there – two must-have instruments 
