Framebuilders - Rear Derailleur Cable Stop Position

I am having a damaged "diver's helmet" replaced by someone who brazes for a living. I'm doing all the prep work and am measuring to keep the new braze-ons in the original location.

I can measure the fore-aft position, but is there a standard for how the diver's helmet is positioned in relation to the center axis of the chain stay? I know they are not centered and are offset to the outside of the stay, but is there a specific guide?

Thanks!

Not really, especially on older frames running older components, which is what I would assume with a diver's helmet. You just need it rotated radially around the stay enough that it won't route directly into the seatstay (for above the stay) or the derailleur hanger (for below the stay). Personally, I don't like diver's helmets, and I would just use a regular split stop.

Not really, especially on older frames running older components, which is what I would assume with a diver's helmet. You just need it rotated radially around the stay enough that it won't route directly into the seatstay (for above the stay) or the derailleur hanger (for below the stay). Personally, I don't like diver's helmets, and I would just use a regular split stop.

Thank you. That's exactly the information I was seeking. And yes it is an older frame (1982 Zullo Criterium). I prefer the function of a split stop, but the diver's helmet is an elegant little piece, despite its drawbacks.

Thanks again.

if there is an above the bb guide, it's fairly typical to have the diver's helmet aligned with the top of the stay