They are quite sensitive by nature, so rarely need to be shouted at unless they have done something really bad (or dangerous) and they should never be physically chastised. Wolfhounds can be trained in obedience, but you must bear in mind that it can take a little longer for the brain to communicate with the rest of that giant body!
As a general rule, Wolfhounds do not make good guard dogs. Their great size and deep bark may prove an effective deterrent to the uninitiated, but as most Wolfhounds are friendly sorts, they will likely welcome any intruder with a wag and a lick! Wolfhounds are certainly not suitable candidates for patrolling and protecting business premises.