Wel it has cured the treble drop as the volume is turned down on the rhytmn bout, I have left the lead bout as standard.
I may have described the mod incorrectly, but its the standard treble bleed as you outlined elsewhere, middle lug and the non- grounded lug just checked the wiring diagram, that's right ?
I don't understand what you mean when you say "there's no treble on the rhytmn bout to begin with"