I can only add to this by saying... I was going down the same path until I attempted to open the right handle bar switch and re-solder smaller wires. Attempting to remove one of the internal switches, I broke the plastic toggle which activates the switch. At this point, I gave up. If I had to buy new switches to replace those which no longer function that well,, why not just bite the bullet and end the misery. The push button switches work as intended with the m-unit. I did rewire my entire bike. But also I used the m-button in the handle bar which eliminated some wires. I also reused some existing wires to keep the oem colour scheme as much as possible.
My project was an entire tear down. I purchased it last Oct. There was so much rust that I could not bare leaving it in that shape. I have replaced the old reg/rec and fuses. The stator and points remain at the moment. Nearly everything has been powder coated.
If you still want to go the route of using oem switches, there is an excellent video by Classic Octane, click
HERE. I have looked over YouTube several times and this is the best IMHO. Easy to follow, no nonsense,,,, and good luck.