Need some help with brake issue

when you get your already ordered shoes, drop one of them into the worn drum, on the worn surface, grab one end and pinch it tight to the drum; then observe how far the other end is from touching. Those shoes, in that worn drum, will not be doing much of anything, until a great deal of the surface gets rubbed off. And during the rubbing, it will get very very hot, because it is only touching on a fraction of the drum, which is supposed to be it's heat-sink. Don't be surprised to be smelling it for a long time, every time you exit the vehicle.
Or, you can take your drums and shoes, down to the brake-shop, and have them matched.
But, I gotta tell-ya, the rear brakes are designed to do no more than about 15% of the total braking anyway. So if yours start out at 1% or 2%, is that a big deal?
Only if they catch fire,lol.