I'd trade Vickery before Griffiths, but if we received a good enough offer.....
What would you want for each of them?
3rd rounder would be fair in an uncompromised draft, if we did really well maybe even a low second (I'd honestly even take a 4th rounder for Vickery at this point) or if they went to good club with quality depth, a good young player from that club who's not getting a game.
If we trade them to say the Bulldogs or Carlton, we won't get much because, though desperate for talls they won't give up high picks, particularly in a draft that's supposed to be rich in tall talent, and don't have quality players or depth, if for argument's sake someone like Hawthorn or Collingwood came knocking however.... the new clubs also have talent they can afford to shed, though I doubt GWS are that desperate for talls ...unless they want to use them as rucks (Mumford isn't getting any younger).
This is where the list managers earn their keep. Though I'd be more confident if we have new list managers come trade week.