Both of my baby corn snakes (who are only about 4 months old, presumably) have had both f/t and live pinkies. The only time they get live pinkies is when I buy a new batch of live every month or so, and then I freeze the rest of the mice. They do just fine with going back onto the f/t mice. Neither of them have missed a meal since I've had them, which I'm glad of.
I also never plan on feeding my snakes live when they are bigger for the same reasons you stated. But I believe that all snakes are different. Some may take live after eating f/t and then switch back to f/t without any problems, and some may not. If you're really curious to find out, go out and buy some live pinkies. Worst case is that your snake doesn't want to eat them, which shouldn't be a problem because the pinkies are small enough to just place in the freezer without any CO2 etc.
Hope I helped
Good luck with your snake!
I also never plan on feeding my snakes live when they are bigger for the same reasons you stated. But I believe that all snakes are different. Some may take live after eating f/t and then switch back to f/t without any problems, and some may not. If you're really curious to find out, go out and buy some live pinkies. Worst case is that your snake doesn't want to eat them, which shouldn't be a problem because the pinkies are small enough to just place in the freezer without any CO2 etc.
Hope I helped
Good luck with your snake!