im using a mountney wheel, how do i know if the boss im using is a traditional or an M-series boss

If its got a big centre then its traditional. The m-series ones are much smaller.

David

are the m-series boss's universal or do i need to get one that is sierra column spacific?

All bosses are column specific IIRC

the m series is 70mm pcd

the classic is 100mm pcd