Start with making the marinade for your chicken. Whisk the garlic, lemon juice and olive oil together. Add the curry and the pepper. Slice the chicken breasts so that you have thin, flat pieces of meat, not strips, and then toss the meat into the marinade. Coat the chicken and cover it. Marinate in the fridge for 24 hours for maximum flavor.
When your chicken has marinated to your satisfaction, set up your rotisserie. Make sure that the end fork on the spit will sit in front of the rear burner so that the chicken will receive the heat while cooking. You may need help loading the rotisserie. Have someone hold the spit while you slide the slices of chicken down onto the forks. You will probably want to do this over a tray or in the sink so it doesn't drip.
You want everything ready for the same time, so while the grill is preheating, mix 1 cup of hot water with the yeast and let it sit for 5 minutes, or until dissolved. Add the 2½ cups of flour, garlic, bone dust and dill. Mix until you have a dough ball forming. Then sprinkle your work surface with a little extra flour and knead the dough for about 5 to 7 minutes until it is smooth and elastic. You can add more flour if the dough is sticking to your hands.
Clean out the bowl you initially used to mix the dough, and turn your oven on to the lowest setting. Pour the 1 tbsp. of olive oil into the bowl and move the bowl around until the bottom and sides are covered with oil. Place your dough back into the bowl. TURN OFF THE OVEN (really important). Cover the dough with a tea towel and place it in the oven. (Best use a metal or glass bowl.) Let the dough rise and double for 1 hour.
Place the rotisserie with the chicken into the rotisserie brackets and turn on the motor. Rotiss the chicken for 1½ hours to 2 hours, or until a meat thermometer inserted into the middle (but not touching the rod) reads 165°F.
To make the garlic tahini sauce, place the garlic into a blender and chop, then add the tahini to mix. Turn the blender on to low and and slowly add the lemon juice and cold water until smooth. Season to taste.
Remove the dough from the oven and punch it down before dividing it into 8 equal balls. Flour your work surface and carefully flatten your pita into a disc as wide as you can get it and less than ¼ inch thick.
Grill the pita for 1 to 2 minutes per side until it's toasty and puffy.
Slice the chicken right off the rotisserie. Serve on a fresh pita with the tahini, and your favorite toppings like tomato, cheese, and cucumber. Serve with the traditional shawarma side, french fries.