'81 K10 instrument cluster / fuel tanks dash switch

[Frankenstien]

I decided to sort out a few dashboard issues with this truck today but I think I need a little help to finish up.
This Canadian-built Chevy has the full Silverado gauge package, cruise control (still works!), auto trans and dual fuel tanks (controlled by a flush-mounted dash switch, just left of the ashtray).
The speedo cable/head has this really annoying squeak (worse in cold winter conditions), the instr. backlighting is out on the left side, the little braided wire connecting the column shifter to the PRND21 indicator is broken and my R fuel tank gauge indication always goes way beyond F, no matter what the actual R tank fuel level. The L gauge indication is fine, as is the actual fuel line switching for both tanks.
So, I have the means to inject molybdenum disulphide lubricant into the disconnected speedo cable but am wondering if my squeak resides in the speedo head itself - is it possible to sparingly lubricate the speedo head mechanism?
As for the instr. b/l (and fuel gauge?) issue(s), I can see that GM's adhesive film electrical circuitry approach to wiring the instr. cluster doesn't stand up well to abuse ... mine has lots of damage from previous owners attempts to change bulbs and/or ?
Just in case the visible breaks in the copper traces at the fuel gauge don't explain the R fuel tank ind. issue, how does one extract the dash switch for testing w/o destroying it?
And, although I haven't asked my GM parts dude about the the little braided wire connecting the column shifter to the PRND21 indicator, I seriously doubt GM would have this separately available - does anyone know of an outside supplier or retro-repair option for this thing?
Finally, I found that removal of the instr. cluster was a bit of a bear. Either it is a poor design, or, somehow, someone managed to inappropriately force the lower left edge of the cluster behind the sheet metal of the dash - getting it out involved pushing up on the dash pad harder than I would have liked. Should the instr. cluster lower left edge live inside or outside the sheet metal of the dash?
Thanks for any help I can get ... FFF