AZ,
Plan on 12-1300 rds for the single stacks, the double stacks with plenty of mags will get through 2k. I've had two 1911 shooters who brought plenty of mags and they stayed with the double stacks for the most part.
I don't know if I can even load 2000 rounds into 1911 mags in two days
"Load Thumb" is quite common with the attendants in the course
Brownie