The evening before the cook, if the fat cap is thick, trim off the fat little by little so there is a thin layer left.
On a sheet pan, pat the pork dry with paper towels. with one hand spread some yellow mustard on the pork on all sides (don't worry about the flavor of the mustard, it just helps develop that wonderful bark).
Spread a heavy amount of seasoning on the bottom of the pork (the non fat side). flip the pork over so the fat is facing up. Spread the seasoning on the top. make sure the sides are also seasoned heavily.
Wrap the pork in plastic wrap and place in refrigerator overnight.
Prep your grill by placing the empty foil pan in the center of the grill. then leaning the coals one at a time so they overlap one another around the pan; making a 3 tier system of coals around the outside of the grill.
The day of the cook, start the coals you prepped the day before. Make sure the coals are glowing hot and well lit before placing the top grate on the grill.
Pour cold water into the empty pan. Place the top grate on the grill.
Remove the pork from the refrigerator and remove the plastic wrapping. Place the pork on the grill. Close the grill lid.
Open your vents all the way to full until the grill temperature reaches around 300° F. Close the vents halfway and wait 20 minutes until the temperature changes. change the vents as needed to keep the temp at 270° F (see notes).
Cook the pork for 3 hours undisturbed.
In the clean spray bottle, mix the Worcestershire sauce, water, and vinegar.
After 3 hours, check on the pork and spray the sides heavily with the spray, spraying every hour for the next 5 hours.
After a total of about 8 hours of cooking (See notes), remove the pork and wrap in tinfoil making sure that it is well wrapped. Spray heavily with the spray before closing the foil. Spread with some bacon grease if you have it.
Return the wrapped pork to the grill and continue to cook for around 2 hours (see notes).
After 2 hours remove the pork from the grill and wrap in multiple layers of plastic wrap.
Place pork in a cooler (or in an oven that's turned off) and let sit for at least 2 hours.
Remove the pork and shred. Serve and let everyone complement all your hard work! Don’t forget to brag about your cooking abilities!