Title pretty well says it all.
Can you use 2 separate IDE devices on a single 7720UW?
Now here's why.
I'm installing a '386SX bridgeboard and to conserve space and, to reduce the number of cables wanted to attach a CF for the PC hard drive along with the CF attached on the Amiga side. Going on the same SCSI/IDE bus would be a heck of a lot easier than a separate controller just for the PC side.