I put a set of rear parking brake shoes on my '15 that have linings. What is the best way to fit these linings up for full contact? Use a file, or maybe a grinder, just let them wear in or what?
The fit or non-fit of replacement shoes has varied over the years. Not too many years ago there were a lot of gripes about how much grinding and/or filing had to be done to make them fit. Maybe all the complaining worked, because the last ones I got were pretty good. It's been awhile, beyond my limited memory for detail, but if I had to do any grinding at all on them, it wasn't much. To answer your question directly, yes, you may have to do a little adapting to make them fit evenly all around.
You're never going to get the kind of contact that more modern drum brakes get because the shoes on a modern system free float and this allows total shoe to drum contact. It's called "self energizing" in that the primary (forward shoe) moves out and the forward rotation of the drum drives the rear (secondary shoe) into the drum at the bottom end of the shoe. The wheel cylinder moves the top half out. The T's system only allows expansion at the cam end. Even if you split the shoes at the pivot that's still all you'll have. At the most half of each shoe making total contact. You don't really need that kind of contact as you can adjust them to lock the wheels even when brand new & un-ground. The truly easiest method is install and use them as they weren't meant to be used, that is to stop the car,and adjust them as they wear.
'Full contact' isn't possible with the cast iron brake shoes, the shoe is expanded only a little at the the leading edge and along the length for a way by the cam. The trailing rear edges of these shoes won't get much wear.
Just fit the shoes to be flush with the backing plate and not get in contact with whirling nuts/bolt ends of the hub bolts holding the wheel hub and drum.
There will be some normal wear that will occur with use. But these brakes are for parking or emergency use anyway...after fitting be sure to test the brakes that they will hold the loaded T on an incline. But never forget to tote along your wheel chocks!
New style lined one piece iron shoe fitted to backing plate.
Test fit the wheel to the shoe without the axle key, to be sure all is well. Issues can arise if the axle is bent, or worn Hyatt's or other things that makes the wheel when mounted to interfere with the brake shoe in one or more spots, then remove some of the brake surface as needed, or best yet find the cause and repair or replace parts.
Test fit of new shoe in wheel drum testing for interferences.
You can see this early production shoe has wide ledge flange for the cam that hits the high points of the hex nuts on the hub bolts.