the usual size for the glass beads used for golf club shafts is 0.002". This means that a 0.1mm clearance on diameter is held perfectly central, and the maximum variation in bond line thickness or lack of centrality is +/- 0.05mm if there is a 0.2mm difference in diameter.
I think in reality, that will make no difference whatsoever to the way the bike works.
Needless to say you can use almost anything that is of the correct size to space an adhesively bonded joint to achieve a uniform bond line thickness. Having said that, I don't think you would need to worry much about this particular job provided the parts are assembled without lateral load.
cheers