Premiere 4K Proxy to HD Monitor via Intensity Pro

I'm working with RED 4K footage. I have imported it and would like to create HD proxies that will play on my HD monitor via my Intensity Pro 4K. this seems like it should be simple, but so far, I can successfully make proxies that play on my computer monitors, but not on the one linked via Intensity. I do not have trouble playing other media on my Intensity monitor.

Here's what I've done:
1. Imported the 4K .R3D clips into Premiere. These appear fine, but are too much for my system to play back happily.
2. Created proxies. I chose from the pulldown menu, "1280x720 Apple ProRes 422 Proxy." This created Attached proxies that play back fine on my computer monitors. But they do not appear on my Intensity connected monitor.
3. I also tried creating proxies using 1280x720 GoPro Cineform. Also, no luck.

I am betting this is a fairly simple issue, but I'm having no luck so far. Anyone have any pointers for me?

Martin

Early 2009 Nehalem MacPro4,1, 2 X 2.6 GHz Quad-Core
OS High Sierra 10.13.6
Samsung 850 EVO 1 TB system drive
32 GB RAM
ATI Radeon HD 4870 GRFX Card
Blackmagic Intensity Pro 4K, Driver: 10.11.4
Avid Media Composer v. 2018.11.0
Adobe Premiere Pro CC 2019 v. 13.1.2
Adobe Media Encoder CC v. 13.0.2.39
Mocha Pro Plug-in v. 6.0.2 build 217.x
Boris Continuum 2019 v. 12.0.4