iOS app, Kickr Core and crank power meter

If I want to use my crank power meter and have Xert control the trainer, do I have to do anything other than pair the power meter with Xert, and of course, pair with the Kickr in the Trainer Control section? I ask, because the procedure I think is different when using Trainerroad. Also…Under Trainer Control, the Kickr offers two modes, “Kickr Core 1DDE”, and “Kickr 1DDE FTMS.” Which one should I pair with? Is “1DDE” the “name” of my Kickr?

Another question that I forgot. If I’m going to pair with the crank power meter, do I need to bother to do a spindown to calibrate the Kickr?

You have it right and would take the FTMS one for trainer control. No need to calibrate the Kickr.
As an aside, perhaps depending on the model, the Kickr can have an option to pair the power meter to the trainer directly via ANT+ so you can forget about calibrating entirely. It’s in the wahoo app (which is only needed for initial setup). More interesting use case is where you want to run two apps via Bluetooth (eg Xert and Zwift) you can connect one to the powermeter and the other to the trainer and they’ll report the same (though Kickr may have more smoothing)

So, regarding the two bluetooth connections for Xert and Zwift, are you saying that by using the Wahoo app to pair the power meter and the Kickr, the power meter’s watts measurement would be broadcast two ways, one from bluetooth from the meter, and the other bluetooth from the Kickr? Can that be done the other way, by using the Kickr as the measuring device and using the power meter’s bluetooth to rebroadcast the Kickr’s measurements?

Yes, and I don’t think so for your second question, but you’d need to check their manual. Normally power meters only send data, rather than receive it.

If you trust your trainer more, why not just use that? And then don’t bother with power matching at all, even in Xert? You can then connect the power meter to Zwift (or whatever) and just live with it being a bit wrong…

I don’t use Zwift. I’m just trying to understand the various options available to me now.