He's got a Firebird Studio with humbuckers which sounds a bit like an SG.
I'd say Stormy Mondays and a fat amp and pedal combo...
I would agree with that. I have a set of Alinico II SMs in an S.G. and they stay round, sweet and warm sounding - with a gentle looseness in the bass.
I think the Alnico IV Mules ( second choice ) - would be too punchy and defined for that particular sound.
F.F.