I am still struggling to get used to SolidWorks' assemblies and mates... It SEEMS like swx has no issue or problem with over-constraining a component. I should take the time to verify this with a simple assembly, but maybe asking you is quicker and more informative. I think I have an assy here with a mate that is repeated twice. Is that possible? Is that a problem?
Also, when I assign an offset mate (with a dimension) what is an easy way to modify that dimension? I currently have to find the mate in need of modification buried in the tree and double click it and then change the value. There has to be an easier way. Any hints?