My dear departed mother loved her chicken cooked that way. I would chop up some garlic and onions - soften them in butter then mix them in the French Dressing. I would cook the chicken up to around 165 then dip the chicken in the sauce and place back on the grill for about 15 minutes to set the sauce.
If we were BBQing for 25 people we still would set two thighs aside and fix them for mom - one thigh to eat then and another to eat for lunch the next day. Thats all since she did not want to be seen as a hog eating too much.