Drilling Holes for Wiring . . .

I have an unfinished detached garage with a second story studio apartment type space above.

I want to understand the requirements for drilling holes in 2x4 wood stud walls for electrical wiring.

I need to run some wiring (14-2, 14-3, 12-2) to a six gang box for switches.

How big of a hole can I drill through the top-plate?
The general rule I find and hear about appears to be 3/4" holes into the center of the stud. That leave a minimum of 1-1/4" from either edge.

How close can the holes be to each other?
Is it 1-1/4" spacing for a 3/4" holes?
If so, is that 1-1/4" spacing from the center of one hole to the center of the second hole?
Or is that spacing from the edge of one hole to the edge of the other hole?

How many wires can I pull through a 3/4" hole? I typically see 2, sometime 3.

And BTW, I attached a picture of the panel and facing the same problem.

Thanks,