Bridge Crane Help

I am having some parameter problems with a simple bridge crane family. It seems the structural W-shapes don't like to be locked to ref planes, and they do not flex? I would like to be able to change the runway beam size, and the girder size.
Eventually I would like to have two bridge crane families: one that is supported by the roof structure, and one other that is supported by columns equally spaced.

First task: When the span is increased the girder length and offset does not stay, and the RW (runway beam) height can not be adjusted without Revit screaming at me.

Any help?

Thanks
Kirk