Tonight I flashed a GB Titan Ridge with NVM 23 (both chips) with Reveltronics Revelprog-IS; very easy.
Next, I soldered pin 3,5 on back of PCB (no need to use jumpers; I verified with ohmmeter before soldering that these 2 pins are correct).
This system (not Designare, but with a similarly built-in TB chip) shows a TB presence in SystemInformation, but no expanded node in IORegistryExplorer.
Tomorrow, I'll replace a second, as yet un-modified GB TR in the X299 build with the NVM 23 board and see how it works.