Zinns shorter formula indicates 184. So 185, or 180, I would probably go for the latter on a touring bike. They have tons of gears, and I don't really feel like walking further to get the same distance. It's like lengthening your stride, but not going any further.

Neither of those is going to affect your frame fitting for a touring bike, pedal strike should never be an issue.

"OTOH, raising the BB 20mm ain't much... i wouldn't be surprised if the BB's on most cyclocross frames are not 20mm higher than those on road frames."

You are certainly correct that raising the BB height 20mm from the low end is not all that much. That is in the current range which is about 10.2-12", but anything in the upper 11s is rare.

On the other hand, Sachs who is a master XC frame builder specifies 85mm drop, and that works out to the lower end of the touring spectrum, contrary to what you might think. But might also set your mind at rest as to the need for heroic amounts of pedal clearance. In other words even with a little raise, you could probably still stay under 11" if you wanted to. And you could probably do no raise at all for most loaded touring.