A putter fitting I think is good mostly for putter length alone. Other than that I’m not sold on “fit for stroke” that Ping was big on when I was there. Years ago after watching and wondering why Phil Mickelson used such a short putter for his height. It was then that I learned that most putters come 36” so people will cut them down to fit. I made mine 32.5” and haven’t looked back. Gets me on the perfect position.
As for necks… I don’t see a big difference from one to the other. I used the Ping putting app and know I have a slight arc stroke. That was nice to know. But I use any style neck really. The slant neck like on the Spider and the Anser style necks are what feel the best though. Has anyone other than me noticed guys like Rory and John Rahm? They change putters and necks all the time, so the people that say certain necks are for certain arcs are wrong… you see it week on and week out on tour.
Another example is the Spider putter with a slant neck is for slight arc. The Ping Tyne has the same slant neck and same toe hang as the Spider yet Ping tells you it’s “strong arc”
So bottom line, get the length right. And don’t think an expensive putter is gonna take care of a bad read or stroke.