shorter brake shoe is always on the front side of each backing plate.
I use my hand to advance the wheel until each drum just slides on easily with little or no drag. You have to slap each side of the shoe assembly to make sure it is free and pivoting around the top anchor post AND to center the assembly on the backing plate (and thus centered in the drum).
After you bolt the wheels on, drive someplace vacant and safe, and backup straight at 5 or so mph, and step firmly on brake pedal. You don't want to skid the tires, but still a rather abrupt stop. This will hopefully advance the self adjuster properly and you will get minimum shoe clearance without brake drag.
