Thanks for the response. First, apologies, I guess in my head I was thinking troubleshooting because I wasn't getting much tonal difference regardless of which position the treble switch was in. It all just sounded a little the same. But it probably is more appropriate in the mods section.
As for more distinction, I'm looking for more treble boost. in the left position, I was getting a very minor boost in the left position, and nothing much in either other (center or right). I'll try socket then jumper(ing) them, or reducing the R value to see what happens.
Thank you all again, I really appreciate it.
Edited to add: HUGE difference with R10 and R14 jumpered. I may revisit R14 (since I have both socketed now).
Thank you so much again. Very much appreciated.