So yerp pulled the 6r80 down today. Nothing looks too rooted in it, not that I'm a seasoned trans builder or anything. All of the steels are in good condition and all of the shafts/gears etc look and feel alright too. I'll get to measuring later in the week to confirm stuff.
The car that the trans came out of had a torque converter failure and had put some metal into the trans which is why I only paid $50 for it. I pulled the trans pump apart to have a look, as that will be where the metal starts it's journey into the trans. Sure enough the small inner gear has some damage and the