As the meat approaches the end of its brining time, preheat your smoker to 275°F (135°C). If using Billows BBQ Control Fan, set the fan-control channel on your Smoke X4 or RFX GATEWAY for that temp. Remove the meat from the brine and discard the brine.
Pat the meat dry with paper towels.
Smear the mayo onto the surface of the meat, scraping it with a gloved finger so that only a bare coat remains.
Season the breasts on both sides with your favorite poultry rub.
Place the turkey in the smoker and probe a breast with your Smoke X4 or RFX MEAT. Set the high-temp alarm for 157°F (69°C).
Smoke until the high-temp alarm sounds on your meat channel.
Use your Thermapen ONE to verify that 157°F (69°C) is the lowest temp you can find in the meat. Remove the meat from the smoker and let it rest for a few minutes before carving in.
Slice it up and serve it!
Note: only slice as much as you will eat. The leftovers are better if you let the breast cool as a chunk then slice the meat for sandwiches off of that chunk. Slicing it all when hot, then cooling it will yield drier sandwich meat.