20 for switches, 18 for tail, and 14/12 for everything else
Way bigger than necessary! Way bigger!
Tell your pal, the M-Unit splits all those service branches into separate circuits, putting out far less amps per circuit than stock. Thus the wire gauge can be much smaller. And if you are using LED lighting in lieu of stock bulbs, even lower amps are required.
The benefit is that he can create much smaller diameter looms and reduce the size, weight, and packaging for installs.
I use 22awg for all the push button controls, and 18awg for service wiring (right side). Even that is larger than required, but many of the components have hard wired pigtails that are 18 and soldering or using connectors from a 20-22 wire to an 18-16/14 is a PITA. So I opt for 18 as a good all around size.
But actually, my original questions was answered correctly (speedo and tach). Was asking because you only had 5 buttons and if an electronic gauge were used, a 6th may have been needed
Nosy Riverfever!