Either that, use spacers with PCD adaptors or have the hubs re-drilled and tapped.
Much more importantly, make sure the centre bore is right: it's this that takes virtually all the load: if it's wrong you must take measures to get it right.
The alternative is get some adaptor spacers. Rob Witney over on the clubcento forum has just got a batch made up. They have been made with a 100 pcd to suit the more common wheel size without the need for wobbly bolts. You will need to PM him for a price.