Testing DC resistance (NB: NOT impedance) is pretty easy with a multimeter set to 1 - 20K range. Note you should always check at the pickups connection points with the pickups switched out of circuit as the pots themselves affect the reading when the pickup is wired in and selected.
1. With the single coils and the deep recess of the ibanez I am looking at doing a "shimming" job and will need washers about 10 to 12 mm thick with an aperture of about 1.5 mm's(almost like a deep washer) . Can i use metal or does it have to be plastic/rubber. (the tonerider pup comes with a rubber grommet that is too easily maleable and not thick enough resulting in the pup being to far below the string.
Use draught excluder (available from hardware and auto supply stores) to replace the "foam" with new. The rubber "springs" are actually surgical tubing. I prefer springs, but with both springs and tubing, there is more chance of the pickup leaning in the cavity (unless it's a tight rout).
2. I noticed that previously a tech had soldered the earth wiring to the tone pot and not the Volume pot , i assume there is no difference in this as everything worked fine but i did earth everything to the volume pot as per diagram.
No difference - as long as all your earths are connected electrically. Wiring all earths to one single point is usually advisable, as it removes any chance of accidentally creating an earth loop.
3. Issue with the neck pup , could it be anything else but earthing?
Could be
any of the solder connections.
4. Not related to installation but the Toneriders came with no idetification on them cept a sticker which removes easily ... i suspect this is to allow them to be branded under different names , is it possible that these are high end units sold at great pricing?
Most pickups have little to no marking on them and when it is there is usually only a sticker. I notice even DiMarzio (Who used to stamp the model in the baseplate) are moving to stickers these days (cheaper).
