Has anyone added higher visibility fixed sights on a 669? I have King-Tappans on a Commander and would like something similar.

I am considering making the same modification to a 669 I recently inherited. Search this site. There is a thread somewhere in which there is a photo of a modified 669. If I recall correctly the owner used a Novak rear sight modified to fit the slide and installed a Sig night sight for a front sight. The installation of the Sig front sight required removing the original front sight and cutting a dovetail.