mines around 26in total length, ive not heard of any larger in tanks but its still growing, the highest ive seen quoted is 30in so plan round that.
They are not very flexible so need a bit of turning space even though they dont move much.
They like to sit along side other bottom dwellers and wont be moved if the other party doesnt like it-this is where you can get problems as other fish can get injured by its body-dont put in with skittish tank mates with soft skin eg perruno.
As for hand feeding -i dont think you would be able to train them if they were in with other fish.
