lol as weapon maker.. i know the struggles.... but..... so far the longest time I've had to go through for the thief to talk to me was just around 20 minutes.... the shortest was ummm less than a minute
just warp to where he is and walk pass him again and again until he disappear... thats what i do... and if he hasn't talked to you and he is gone.. then he is on another location.. repeat until he says stop following me
PS: I've made like 20 weapons now.... xD or more so i know my way around those stuff