Recommendation: For a piping or tubing part, include one configuration for each size and specification that you need. To create your own pipe or tube part, copy a SolidWorks sample part to the library folder and give it a unique name. Then edit the design table to create the configurations you need. The length attribute is not used.
Recommendation: For better performance, create several different elbows, rather than creating configurations for all sizes, angles, and class radii in a single elbow part.
Reduce file size by deleting part configurations that you no longer need.