hub adapters, which wheel bolts?

hi guys I'm looking at putting some genuine vw alloys on to my 6n using adapters to make the hubs 5x100, the 5x100 wheels use m14 threaded bolts where as the std 4x100 use m12, what bolts do you lot use when converting?? just been looking at fk ones and it says to use the existing m12 wheel bolts, are these ok as there smaller then the bolts designed for the wheels?

i can have hub adapters custom made to my requirments with m14 bolts but will end up more expensive

cheers