As I've stated in a number of post previously, I have attained a nice brown tone with Ilford FB warm tone developed in Zonal Pro Warm tone developer, then afterwards toned in Kodak Selenium toner 1:9 for about 4 minutes.
You don't see much color shift until you go into the selenium. It has a chocolate colored tone. The color of the tone seems to relate to the dilution of the Zonal Pro. I use it at 1:6.