Hi Webb
Temperature Control works with
Nickel
Titanium
Stainless Steel
The TFV4 is using Kanthal and not compatible. If you are building on the single RBA then you need to Specifically buy the right kind of wire. My suggestion is to begin with Nickel or Titanium. The Releaux seems to have trouble with Stainless Steel in TC mode.
Also a new Firmware VS 3.0 came out which will give the ability to adjust TCR and use more different settings.
Good Luck!