Thanks Sandy and everyone who posted on this. I'll look forward to any more posts that come into this thread, but I think I'll work through the rest of the rolls on this job by doing minimal agitation with 2:2:100, HCA and lose the soak in the spent developer.
The 10-minute presoak is just because I'm paranoid about bubbles sticking to the emulsion during long periods without agitation, and about streaking from jets of developer flowing through the sprocket holes. I figure if the emulsion is nice and saturated, I might reduce the liklihood of both. Also, during agitation, my reel doesn't leave the solution. I just stick a couple of fingers in the core of the reel and move it up and down beneath the surface of the developer for thirty seconds, then rap the bottom edge of the tank to dislodge any bubbles. Of course, the reel does come out during inspection, but I agitate afterward, so hopefully that does its part to reduce bubbles on the film surface.