how hard is it to switch from live to f/t

[TeaNinja]

my snake eats live and i've always just fed live because i know it's more natural and that's what snakes are used to. but not only is f/t more safe but i feel bad watching big rats die because they are really smart animals (my snake just ate a rat i had to house for over a week)
also he's around 2 years old and i only got him a month or so ago, i assume he's eatin live his entire life. i'm just thinking it will be near impossible because i watch him sit VERY still and wait for the rat to walk up to his face before he strikes every time. maybe if i used food tongs to dangle a rat in front of him, but i think he'd know the difference. (and they get kinda violent with their strike/constriction)