[Avid-L2] HDR Nit Level project vs. adapter vs. monitor?

I picked up a new C9 LG OLED and am having it professionally calibrated for both SDR and HDR.  I haven't looked up the exact specs for the LG OLED but I'm guessing it's going to be around 600 Nits.

So I've only dabbled with HDR in Avid and a bit more in Resolve.  I know in Resolve I can set the standard 2084 to 1000 Nits and I think there is also a 600 Nit choice.  With Resolve I am of the understanding those settings will limit the output to a max output of 1000 Nits, something like 728 on the Resolve scope, or 600 Nits etc...  I haven't played with Avid enough to know how its' architecture works in this regard.

I have the Aja Hi5 4K Plus to convert SDI to HDMI and turn on the HDR flag.  The control panel for the Aja also has choices of 1000 Nits and 600 Nits.  I know the unit works and sets the HDR flag when set to 2084 mode and will trigger HLG when is is set to HLG.  I know the delivery spec for HDR typically is 1000 Nits for Netflix and I assume other networks etc... 

My question is is the Hi5 4K Plus in essence tunneling into the LG OLED and telling the monitor the signal is 1000 Nits or 600 Nits based on the control panel settings?  I know it turns on the HDR mode and it seems to work but I don't quite understand what is going on under the hood.  Usually tunneling happens with a eCMU hardware unit but now with the right Black Magic hardware I/O, "Ultra Studio 3 Extreme and a card version", Resolve can tunnel with it's own iCMU.

So is the Hi5 4K Plus tunneling in the traditional sense I've been told which means it is talking to the Dolby Chip inside the LG OLED or is it just turning on the HDR/HLG mode?   Given the delivery spec is 1000 Nits it seems the project should always be in 1000 Nit mode but what about the Hi 5 adapter should it be set to the destination monitor capabilities, in this case 600 Nits, or set to 1000 Nits to reflect the actual source signal coming into the adapter?

Just spinning in my head and I'm trying to suss this out.

John Moore Barking Trout Productions Studio City, CA bigfish@pacbell.net