Using the assumption of 80% of undecideds going R (which I believe is the high end of likelihood)
Fetterman 50.4
Oz 49.6
Shapiro 52
Mastriano 48
These are the "worst case" numbers for dems, imo. I think it's more likely that polls end up being right assuming 75% of undecideds go R. That'd bring Fetterman to a 51.25-48.75 victory and Shapiro to a 52.5-47.5 win. Sounds about right to me if things keep going the way they're going.
Yup, that's pretty much where the race stands right now.
It's not the 50% for Shapiro that's questionable, it's the 40% for Mastriano (although that what's Scott Wagner got in 2018).