I've used copper tape and shielding paint.

The only before/after I can offer is from my Mexican Strat - when I got it is only had some foil on the scratch plate - I took it to bits to add the Dave Gilmour switch (switches the bridge pickup on regardless of 5 way position so that you can get all three and also neck and bridge on together) so I added a full covering of self adhesive copper foil and it did improve things so was worth doing.

@frocesterbill I've got plenty tape, so I might just go with it on future builds. Quite enjoyed doing a wee bit of "upholstery" in the cavities...

The copper stuff i used has conductive adhesive so you just overlap to get electrical continuity and you can solder to it to connect a ground if you need to.

It is going to be most noticable if you are in a noisy environment (flourescent lights, etc...). I use the conductive paint from stewmac - it takes 3 coats and all day coz you have to wait for it to dry in between coats...

I have used some shielding paint from Mahogany Green Luthier Supplies who are based in Ireland - about £4.50 for a small 30ml bottle.

Applied some to a scrap of wood to test - one layer - quite thick but goes on in a smooth matt black layer and wouldn’t trickle through control holes onto the front of a guitar - tested with my multimeter - scratched surface and the scratch showed silver - resistance over 10cm was about 2 Ohms.

Have now used it on my Firebird build.

They are on eBay and do sell bigger bottles.

Website www.mahoganygreen.com

Here is a link to the Stewmac stuff I sometimes use - needs 3 coats to build up full conductivity - - takes hours to dry between coats so no good if you are in a hurry!

https://www.stewmac.com/electronics/shielding/conductive-shielding-paint.html

I use slug barrier tape...cheap as chips compared to normal copper tape.

https://www.amazon.co.uk/Slug-Tape-Copper-Repellent-20mm/dp/B00DDVFS7I/ref=pd_di_sccai_2/262-4706217-6017065?_encoding=UTF8&pd_rd_i=B00DDVFS7I&pd_rd_r=23d8c23e-f747-436b-8967-bdeb7fcfd814&pd_rd_w=LTtDW&pd_rd_wg=x6IPM&pf_rd_p=4d243aa6-d88e-4de2-9cbb-xcd5cf6bb2669&pf_rd_r=EZAEX27B33JXFFPFR9T0&psc=1&refRID=EZAEX27B33JXFFPFR9T0

It hasn’t got conductive adhesive but if you fold over one end slightly and overlay then put another piece over the top it works a treat.

just another alternative?

lots of edits as I can’t get the url to work correctly!