AEO - it's just that this model has the dust cap directly overhanging the cone flats, which I haven't run into on the other ('90s era) Shimano hubs that I've worked on. My worry is bending/damaging the soft metal dust cap with the cone wrench.

Looking at it again, it might be that there's barely enough room for my cone wrench once I clean off the old grease and grime. I'll report back once I've tried that, as it seems pretty clear from your comments that there is no "secret tool" that I'm missing.

dp - thanks for your suggestions -- I'll go that route if the cone wrench won't fit in the cleaned assembly.