The following may be obvious to many players, so apologies if this sounds ridiculous. But doing some tone testing yesterday, particularly as I was fooling around with my Qtron+, I think I had something of a personal revelation. Now, obviously Jerry's pick attack varied all over the place but I think on average he must have picked his strings pretty damn hard. Deliberate, controlled, but dug in.
I think a lot of us who may be (mostly) bedroom players have a habit of being "too gentle" with the strings--at least I say so for myself. But when I was trying to wrangle some tone out of my Qtron it didn't sound good with my typical pick attack. Experimenting, I started really focusing on strong, deliberate attack and all of a sudden things started to come together. Even playing clean but digging in much harder, I think, improved my tone...in the general JG direction.
At about 1:08 mark in clip below, I kick on the Qtron+ ... I'm really digging into the notes here & the JBL cones were rocking. May be the closest I've ever gotten to good envelope filter tone:https://soundcloud.com/lunasparks/2013-04-06-fire-jam-edit-1984
Anyway, food for thought....