Well I replaced the driver's side rear drum (fit just fine), then I adjusted the shoes on that drum (much easier to do so now- drag is very even). Before I did the adjustment I tried the e-brake experiment- I mashed the brake pedal a couple of times (went down to the floor every time- didn't go instantly down to the floor without resistance, but I had almost reached the floor by the time I felt any appreciable firmness) to center the shoes before adjusting them. Then I applied the ebrake as far as I could go and checked the cable- it was pretty taut. Tried the brake pedal again but got the same result- no difference. So now I'm suspecting the front brakes. I'll finish off replacing/adjusting the right rear drum then tackle the fronts to see if something's going on with them.

Will keep you posted-
David