Hi Jackenbach, rocket science it isn't but it aint easy building a bike up from parts! My A10 was thrown together project, supposedly complete but actually it was missing lots of the smaller parts and of course some parts were wrong (off different bikes) or worn out, on that project I started as you have with the frame resto (took a year) and then bought parts as and when I needed to until it was done, final parts bill was $$$$$, I never really tried to work out what was missing or needed but had I done so I might have sold it off, and bought a better bike with the proceeds.
For my current B31 project I'm trying to "dry build" it and place an order for parts all more or less in one go so I know the cost and time involved, and also do the painting all in one go, I've not found dry building to the standard I'm after as easy as I expected as I've found myself restoring or making parts in order to be sure it will all go together ok come the real build, for example I've found thats its not really possible to properly dry build the primary drive including getting the alignment right without the missing clutch centre bearing. To avoid pressing in bearings in twice I even resorted to grinding the o.d. of the worn front wheel bearings so they slide in the housing easily and then I can respoke the wheels, get tyres on, and finally fit the wheel and then be able to make up mudguard stays the correct length for the non standard alloy guards.
After stripping and spending many hours repairing tin ware I found I could not leave the parts bare and rusting so ending up painting them which was not what I planned as part of a dry build method.
I'd be interested to know how others approach building a bike up from parts!