which direction are the drum brake ratchets intended to turn?

Not they pull down ?

 

There are right-hand threads cut into one of them, and left-hand threads cut into the other.

The idea is on both sides of the car they should get longer when the adjust lever pulls down on the wheel.

If you mix them up side-for-side, you'll have adjusters that get shorter, and auto-deadjust your brakes.

Or if the aftermarket manufacturer happens to sell you two with the same thread, in bags labeled L and R, one of them will work, and the other one won't.

 

Am I getting this right: if there was no auto-adjust, then they’d “work”, if you very regularly adjusted them, and cottoned on to which way the star wheel need turning to lengthen. But the auto adjuster on either side performs the same (downward?) motion, so the contrarian adjuster is doomed to disadjust (shorten).

 

You're getting it right. And the one 'disadjusting' will probably spin itself right down to minimum length in short order, because the adjust lever clicks whenever the parking brake is used and the clearance is excessive, so once the clearance first becomes excessive and it clicks the first time (making the clearance worse), it'll be one more click for each use of the parking brake from there on out.

 

Yes I have these tools called brake spoons we used to adjust the shoes to keep everything nice and close so pedal is hard and minimal travel etc .. once a month two clicks . Just takes a second car on ground reach around w spoon click click..