Look at the top of the catfish forum for my catfish sticky, there's good info there for the tiger shovel nose. Just for quick reference there's some good links there too. Max size will be 4-6ft.
Yes about 4 - 6 feet in total. They grow really quickly due to hybrid vigour so make sure you have the right accomodation. They eat huge amounts of food so same again for the filtration. They can be kept with other big cats too but you should still be weary of fish you put in there with them because of there huge mouths.
Honestly, if you need to ask, then this is one of the fish best left alone. They grow really fast, eat a great deal, and are startled easily. Unless you've got a huge tank, forget about it.