You can set a HotFolder inside of CaptureOne, and then use CaptureOne to tether. Downside is you're importing RAWs so that means eight seconds or so per image, due to lame decision to use USB instead of FW.
Or, you can use EOS Utility, but same deal: eight seconds if you're importing raws.
Or, you can use EOS Utility, with or without linking it to DPP, and if you're willing to download cards, you can see the images come in much faster, around one second each. this is the workaround:
1. Put a CF card in Slot 1.
2. Put an SD card in Slot 2.
3. Set the camera to "record separately".
4. Set the camera to "Playback only Slot 2".
5. Set the Slot 1, the CF slot, to record RAW.
6. Set the Slot 2, the SC card, to record JPG SMALL with compression.
7. Open EOS Utility, and link it to DPP.
8. Hook up the USB cable to the Mac.
Downside with this: every time you open the CF door on the body, it drops connection to EOS Utility and it takes about thirty seconds to reconnect. Obvious other downside: you must remember to download the CF RAWs onto the computer, since you're only viewing JPGs on the tethered computer.