I am attempting to convert my late '80's Fuji Palisade to a fixed gear. The dropout spacing is 135 mm and my LBS told me that is too wide and I would need spacers to compensate for the difference. I am planning on buying a ready made wheel with a flip flop hub.

Where do the spacers go and what do they do? Is that the only way to correct for the wide spacing of the dropouts?

Also, what are the different types of bottom brackets? Will a different bottom bracket solve the problem of improper chain line due to the wide dropout spacing?

I think this is the only problem standing in the way of my conversion.