I rode a few sections of the course last night, some of which form part of my local loop.
It is dry and dusty in the parts that use the standard trails, but the bits that veer off into the off-piste areas are quite soft still.
Tyre wise I reckon a fast rolling tyre on the rear and something with a bit of grip up front would work very well. My biggest concern was washing out my front wheel in the corners being unaccustomed to riding in such dry conditions.
coming home from a ride in Lochaber with a dusty bike is a pretty rare event :)