Maybe I'm saying something stupid here, but hope it helps:
Solution 1 seems to defeat the purpose of this circuit, an solution 2 would have bleed from the other channel.
If i understand correctly the mechanism of a pot wired w/ lug2 as the feeding wire, you would be applying a resistance to either outer lug, not killing the signal completely at the opposite end once the pot is dimed.
The only convenient solution i can think of would be a dual pot configured like the Gain pot on the Maxon OD820: while one side gets boosted the other is backed off.
So that would mean:
ALug 3 and BLug 1 jumpered and attached to your input
ALug 1 and BLug 3 jumpered and going to ground
ALug 2 and BLug 2 to the two outputs.
No f**** idea if this would actually work, just thinking out loud here
gotta breadboard this and see.