Lösch was appointed in '94 making him the longest serving. Scroll down to 'Governing body members' section on the link.
https://en.wikipedia.org/wiki/Governing_Body_of_Jehovah%27s_Witnesses
I don't know about Lösch being senior as GB members are supposed to be equal... or what info you're trying to get at but the money end is operated by the President of the 'Watchtower' (the President as of Adams appointment is now a non-GB position for the first time and that was made official off top of my head around 2000) and that is Don Alden Adams.
https://en.wikipedia.org/wiki/Don_Alden_Adams
Edit: Interestingly, Don's brother is vice president on another arm of the Watchtower. I'm of the mind that any digging for treasures should be done on this side as opposed to the GB... I see the GB as the smokescreen. Watchtower/the money side is where it's gonna be at!