Here is my $.02 on it.
Wiring stuff should not be much of a maintenance issue, purchase or borrow as things come up.
For the hardware, the biggies are screws, and nylocks.
You will remove a lot of screws every time you do much of anything to the plane maintenance wise, and occasionally a nylock or two.
I would get the nuts from Vlad, like he offered, till you get a feel for what is needed.
Buy the screws by the hundred from ACS. They are cheap. Get #6, and # 8, 3/8 and 1/2, like recommended prior. Get both flat head, and round head, as per the call outs on the plan.
The compartmented plastic boxes are hard to beat, I use them for a lot of goodies.
Cad plated steel screws are a lot more durable than stainless screws, if looks are an issue go stainless, other wise, go cad plated.
As soon as a screw starts to show any sign of striping the head, toss it.
Ditto for the screw driver if it is worn.
Get a bunch of spark plug washers, and oil screen washers while you are at it, both of these should only be used once.
Good luck,