Sounds like more hassle than I could be bothered with to be honest so don't think I'll bother.
I had a bad experience with spacers and incorrectly sized bolts many many years ago, long story short I was supplied multi-fit wheels (Ford offset to fit a Citroen) which needed a 20mm spacer to correct the offset, he supplied me bolts that although did thread in to some degree were not long enough and as a result after a few months the car started making some really strange noises and wrecked the hubs. When I went back to them they just refused to accept responsibility
Anyway thanks for the info guys