Update: After 3 trips to the shop, turned out the master cylinder was the culprit. It was "leaking" internally. Turned out to be a hard problem to pinpoint 'cause there was no fluid loss externally. Now the brakes have no more than 1" play (they were almost the floor before) and WOW, what a great feeling of stopping confidence. Just wanted to pass on the experience for everyone's benefit.
Deb 71SB