Thanks; at least it ain't 'cause we didn't try (for new Computer).
Yes, I must have misunderstood Snap Grid, that the points are not Constrained but still moveable, but I shall re-build the Real Bowl from Scratch (which I can now do in a few minutes, compared with the first attempt, when the Real Bowl took Days), with Overlaps, Tangency wherever possible, and very wary of Snaps. The next challenge will be to put ShapeStrings to label the Pipe.
I had thought maybe my Graphics Driver was seeing the Line elements as width not-equal-zero (I wish I knew how to insert inequality symbol, that's way cooler), and cumulating them with the Dimensions, or something, anything to blame the Computer, but it's prob'ly better to limp along with what we're used to for now.
Thanks all again forever for your pearls of wisdom and insights.