The earlier ones adjust when stopping going backward, but somewhere in the earlier '70s or so, they adjust when going forward and stop? Either way, you have to brake hard enough to get the shoes moving rather than just easing into them to slow down.
In theory, the adjusters should adjust regardless of the initial adjustment, but that "getting close" manual adjustment, to start with, gets things to where they need to be quicker, I suspect.
Rather than the time-honored spinning wheel/brake shoe just starting to drag, then back-off a notch or two, you can also get a brake shoe/drum caliper at many auto supply vendors. Use the caliper's side to check the ID of the brake drum, then take the caliper (and that "size") to the brake shoes and adjust them so they just fit into the brake shoe side of the caliper. Then install the brake drum to the wheel brake. That way, all of the brakes are adjusted "the same" with less general effort, it seems to me. A good investment, to me. Of course, once re-assembled, check for correct operation.
Just some thoughts,
CBODY67