Never built one from scratch - but having done a certain amount of spannering on our PFA Pitts S1, I'd say the one vital requirement is that you have a large amount of extremely bad language available - I understand Peter Cooke and Dudley Moore have prepared some excellent preparatory training material, but having removed and replaced the fuel tank in the Pitts more than once I've found the requirement for profanity well beyond anything they ever aspired to. In understand that replacing the main gear bungees does require hearing protection, to prevent ear damage caused by repeated use of some of the very earliest Anglo-Saxon phrases yet discovered.
But it will all be worth it in the end.....