Most (all?) of the Ballys I’ve owned have that tapered flute routed in them for the rail, which looks like you’ve got setup per your previous post. I haven’t come across anything fancy on a classic Stern.
This is NOT a dig at Taylor but I did order some (very nice) rails from him for my first scratch build; a Quicksilver. They were dimpled and pre-drilled. I kinda wish they weren’t because there’s always going to be a margin of error. I ended up having to move a couple holes as a result. Not much but still. Those Stern rails so basic, I didn’t have much of a hard time aligning everything when I made my own rails for my Star Gazer or second QS build.
It’s that tapered routing I don’t know how to do that’s preventing me from re-doing my Dolly rails myself. I don’t have the pf pulled apart right now and don’t have any extras to offer as donors. Glad you’re starting to offer these for us again and look forward to your library growing!