We had a couple of days of ministerial training back in 2011 in Dumbarton Kingdom Hall.
The Glasgow congregations are all pretty "close" - I do know someone from Dumbarton (who is still in), but I'm not sure they would go back as far in history as this. You might also try people in nearby congregations such as Clydebank, Paisley/Renfrew, Port Glasgow or Maryhill/Bishopbriggs.
Perhaps slimboyfat or dozy might know older folks in the area.