Hi,
Do you know what he was eating in the past?
Just in case he was on live and resists F/T. No point in buying a freezer load of things he won't eat.
If he hasn't eaten in a while you will want to feed him smaller prey items than normal to gently restart the system.
Then, once he has had those you can move up to the normal feeding size - I'm going to say he should be on small rats at his size normally.
You might also want to read more about tub and tank sizes before deciding what to build him - too much space can actually be a bad thing for Ball pythons.
Have a read through the caresheet as well.
dr del