It is important that the chicken pieces are really dry before putting them in the bag to coat, because otherwise the coating clumps up and sticks to the bag instead of to the chicken! Also, you can use a vegetable peeler to cut slices from a stick of margarine, making them as thin or as thick as necessary. I do it this way for (fish) fillets as well. The slices lie nicely on the fillets and melt evenly during cooking.
I find that the sauce is really enough for two chickens, so you might want to cut it in half. However, if you want to serve it over rice, you need more sauce, so leave it as is. Try it once and see what works best for you.