how do you use workset in your different scale projects?

Andrew is correct. but we really need to have more info in order to answer the question correctly... or narrow down the options!

Need to have a "Shared Grids and Levels" workset as a minimum.

Worksets can do two things for me. One - Allow different folks to work; and Two - Make things easily filterable.

Are you refering to different types of scales metric vs imperial?
I aggre it the above answer, what is the purpose.
Worksets are contained in the current project you are working on. Why would you be concerned with another project. If you transfer OBJECTS from on project to another, they come in at the same size.