The allowable loads, with attendant dimensions and welding definitions, for Shoes, Guides, Line Stops, etc. fall into the realm of so-called Pipe Support Standards. All engineering firms who are engaged in piping design activities carry such a document. My prior working with E&C companies involved the Pipe Support Standards, and they are involved. My advice here for you is search for some Standards developed by others before embarking on designing your own. This isn't a rule of thumb matter.