Got up this morning to find that all of the overnight exports are mangled. Not sure why, but something in the exporting went bad when some other program stole memory or something. I blame anti-virus.
Anyway, the main mesh is all flickery, it drags like mad, and a new shadow issue seems to have been introduced in the shallow water areas. There is now a big + symbol in the middle of every shallow water tile. Looks really weird.
I did find that the 1500 under tile waste was sufficient to get rid of all the other large junk, and yes it does make it really annoying in the toolset to work with. At least placeables automatically find the ground at the mouse pointer...except where there are walkmesh errors not taken care of.
Tiny bit more work today and then export again.