Haven't actually tried using the Tascam Model 12 as an audio interface for the computer... still running it by itself.
Turns out I need to update the firmware, which has natively supported Reaper since version 1.30
Tools Needed
- USB-C cable to connect the Model 12.
- Reading the update manual. :)
All needed info nicely provided by Tascam for Firmware update to 1.41 as 1.30 added Reaper support. Had no trouble connecting the mixer to the computer as a USB device, then copying the firmware update to the /utility folder.
Works like a charm!