I bought a dynamo regulator for a car a few years ago. You might still be able to get one - and find a circuit diagram in a Haynes Manual.
You cant avoid using the dynastart unless you fit a starter motor - which is quite a job. However you can add on an alternator (and diconnect the charging side of the dynastart)
You can design, have made and then fit a pulley to the centre of the flywheel. Thats fairly easy.
The more difficult bit is to make up a bracket that will hold a car alternator in the right position. Following advice from my engineer I made a bracket in wood and gave it to the engineer to fabricate in steel. It wasnt expensive.
If you are facing the flywheel there are several bolt holes and studs you can fix the bracket to.
Sorry I'm a bit vague. I did the work in 1999-2000 and I've since bought a new engine.
