Try and have an idea how to mike up your cabs. The studio folks should have experience with this. Expect to have to wait a couple of hours for the drums to get sorted, mikewise. This time is well spent though-don't get too impatient-if the drum tracks
get sorted early it is easier to do overdubs etc ie going back to re-record a rhythm track is nigh on impossible.
The last time I went to a studio, I used a POD, and it took 2 minutes to get a useable sound. Maybe not the best tone in the world... but time is big money and in my 6 piece band, I didn;t warrant more than the aforementioned 2 minutes!