I'm attempting to duplicate the techniques of Bill Nitler, as in his video, done by the ACGG. It's the only reference I have. He used internal heat to solder upper and lower ribs all at once. Heating from the inside prevents the flux and the joint from getting contaminated. He used some sort of 5/95 lead-free solder, and considering that when he was alive he was the only factory-authorized Purdy repairman in the US, I figure he'd be a pretty good man to copy from. Thanks for the replies.

John Farner
Eagle Machine Gunsmithing, LLC
Corrales, New Mexico