Mike: Are you using the correct procedure for bleeding all for wheels? Yes, you do shut off each speed bleeder each time you fill the master cylinder and Yes, you must bleed the brakes with the drums on the car and brake shoes adjusted so the shoes are not retracted far away from the drums .
Too far away and the shoes will not give any resistance to pedal pressure. That's the way I do it. In fact, I adjust the brakes BEFORE I bleed them to avoid this problem.
As you may know, you do them in this order:
LR, RR,LF, RF. Here is a helpful video.
https://www.youtube.com/watch?v=3VMV51FUA7A
Here's what the Speed Bleeder folks say:
http://www.russellperformance.com/mc/speed-bleeders/