the bolts are 'BZP' high tensile steel, i was advised that they would be strong enough, opinions welcome though?
i decided to space the hub rather than the wheel because it was a lot cheaper and also i wanted to use my current wheel bolts
the spacer options were either a 15mm bolt on type spacer which the cheapest i could find was £120 for a pair, or the standard hubcentric type using long bolts which were around £60... but i then had to run the crappy looking bolts and also had to pay £30-40 for a set of longer locking bolts