> That said, it seemed to me that longer cabling was less in use with G- and I-machines, but that's just me looking over scraps that went onto internet.

The XL400 and XL1200 were large & loud beasts. You would not want to have them near you.

> Symbolics also definitely had an edge in graphical processing, though I've seen mentions suggesting that for pure CAD works that didn't require high-definition video output Explorers sold quite well?

Symbolics was also widely used in HDTV quality productions.

For CAD work I have no idea how big the market was. But for example iCAD was probably one of the applications that were making new stuff possible via parametric CAD. Then there was CAD in electronics and chip design...