What an awesome project. Last year I had the opportunity to cob job repair some antique windows (in place – mostly just bondo). We got a quote from a reliable window contractor to remove and repair the sashes for $10k per window. Crazy price. The owner balked and I ended up doing it myself, but like I said – it was a cob job and not a real repair.
Also, since you mentioned sapele, I have a little experience with it. I had to repair a sapele veneer cabinet in place a few years ago, so I called the millworker that made it to see how he finished it. First, he shellaced it, then used a satin poly. I followed his instructions and it came out perfect – totally matched the existing finish. To this day, I don’t know why he used shellac first, but shellac does slightly “amber” the color even when its not amber shellac. It looks nice. Gives sapele a rich color – the lighter highlights become golden more than blond. Looks great.
Losing fingers since 1969