Been all through this (like others) and I ended up scouring Ebay for the driver's side mirror, then for the passenger side, went to a Mustang mirror body and lens, and a very good repro mount from WCCC. This was not a cheap operation but it looked like a million dollars when finished! If you want to simplify the whole operation, WCCC have everything you would need! I did not know whether you knew that '69 models did not come with racing mirrors on the passenger side (70's did) but it is certainly a worthwhile and useful addition
Good luck with it!
When I bought my '68 Cougar, there was a brand new passenger door mirror lying loose in the trunk, it looked exactly like the drivers door mirror, but when you tried to attach it, it just cleared the glass by a whisker as it was a mirror for the Mustang of the same year. The stem is more upright for the Mustang, where the Cougar, needs the stem to have more of an angle, leaning away from the glass. Bought and installed the correct mirror and sold the Mustang one on the net, for NZ$65.