Unlike Donald or Scrooge who are hardworking, Gladstone is lazy and overdependent on his luck. He has no ambitions in life and is incapable of long-term planning. Gladstone is also arrogant bragging about his luck and believing that with his supernatural luck, he can get out of any situation and can breeze through life without having to get his hands dirty. In this version, he thinks he's a hot shot and likes to narrate all the time 

Voice something like Troy McClure low and professional