Hey Mike thanks for posting on this topic, for me it was a mistake not to look into xRefs some time back and Ive been fighting large size mechanical drawings for some time. But after reading your post the penny just dropped, that using xRefs has many benefits and more.
FWIW, I was constantly trying to reduce the file size of a drawing ( 95mb) but having little success and for those that have been using TCW for years know ( I didnt) that xRefs save on the total file size big time. But theres more, using xRefs in the revised drawing has reduced my file by 70mb, where many individual parts are now external to the main drawing. Wow!
When loading the revised file it so much quicker to load in all respects, animating the revised file is so much quicker in that it appears to consumes less memory from how I see it here, as the xRef is displayed as an image without the data load for that xRef.
Old size: 95,750kb
New size: 25,155kb
Total xRefs used: 20 ( total files size of 69,255kb )
TCW V21, 2016-2019 PP, Animation Lab V5, TurboPDF V2-V3 & LightWorks Rendering Engine mostly.