Most moderate-to-large sized towns will have at least one shop that still does electrical rebuilding. I'd suggest finding that shop, and get the field coils installed by them, with the proper tools. Pole shoe bolts either come with a BIG screw slot, or sometimes a square hole that resembles a 1/4" square drive. From long-ago experience, I can tell you that there's NOT a 1/4" drive tool anywhere that will survive trying to remove or install one! If the fields aren't installed securely, they can work loose and wreck the starter when it's under high magnetic load during cranking. Most field coil connections are copper-welded, not crimped or soldered. If they're loose, replace the entire field coil assembly- - - -don't try to repair it. The resistance values are so critical a repaired coil simply won't flow enough current to develop the right torque. Once you've got the field system assembled, the rest of the rebuild should go pretty well.

Have fun!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!