I have no clue on how to tell you to switch them to f/t but i have been feeding my ball f/t since i got him and all i do to heat the mice is i put the mouse in a zip lock baggy fill a bowl of HOT water and put the bag in the water for like 15/20 min. You might have to put something on the bag to hold it down in the bowl cuz it will float if not lol. But i have had no problems with my snake eating with my method....

And i just use tongs to dangle the mouse in front of the snake until he strikes and takes it.
Good Luck!