My grey marl freedom sleeve Cushman sweat, size M, currently measures:
53cm p2p
58cm back length
56cm pit to cuff
It's had many washes (no drier, yet) and many wears - has also been worn out of the last wash for these measurements.
Hopefully that's useful to check against size charts.
The one dimension that doesn't work perfectly for me is the sleeve length, I need to cuff the ...cuff, to get it to the right length. An issue I don't have with my new Butcher Products raglan sweat.
I've noticed different materials wear & age differently, which sounds silly to say, but I'm meaning even on garments you'd expect to function the same. e.g. I have 2 Toys McCoy tshirts of the exact same size and style, bought together that have aged substantially differently and shrunk / stretched differently.