you need a good quality 10 ton press and you need to make a tool for pressing the bushes out/in. I used a cheap press and bent it.
A front brake piston out of an old ford courier is close, you will still need to machine it down though.
best bushes are genuine nissan ones, slotted if you need flex.
if your bus is lifted more than 2 inches you might want offset bushes to give it some more castor.