My big advice with F/T is do not be afraid to let the snake skip a meal or 3 to get hungry enough to eat the F/T. This may not always work, but give it a shot. Also warmth is key. I use a hair dryer for about 45 sec AFTER the rat is fully thawed, right before I offer it, and that does the trick. If they start to immediately track it, then it is hot enough.
x2 It won't hurt your BP to miss a few meals, but it might get him hungry enough to accept a "microwave dinner" instead of live. (Disclaimer: Do NOT ever actually microwave a rodent. IT WILL EXPLODE.)