For the tubing look for "Latex rubber surgical tubing". Whilst searching, I've just ending up buying a 1m length of 3mm ID x 6mm OD tube, which is about the right size for all but the largest pickup screws. Cost me £3.50 (around $5.80) including 'free' postage on eBay. But you'll need to be able to cut it square, otherwise your pickups will want to tilt.