Another timing curve question

I don't recall the slots being grossly different in location, but now that you mention it... I'll eventually be removing the carb from the manifold to install setscrew-type idle air bleeds, so can look closely at the t-slots then. (It's an old 4780 double pumper for someone who's better acquainted with the fine details than I am).
Quick test if a richer idle may help- stick some wire down the air bleeds. Secure it under the air filter base gasket