You can change the rake and trail (simultaneously) by raising/lowering the forks in the triples, or raising/lowering the rear by adjusting the pushrod or the yoke, depending which you have.
Limited by when the wheels start hitting things at full compression...
You can change the only the trail with offset triples.
It's not a setup issue for geometry. It's a clearance issue of tire and valve cover. Offset tripples have a degree change in the trees then? Meaning the holes in the trees are machined at an angle, and not 90 degrees like normal? Anyone know who makes some?
The only way you'd be able to use the 9*6 eccentric is if you cut off your head tube & replaced it with a 9*6 unit. Anyone who machines triple should be able to make you whatever you want for angle & offset. I know there used to be people who made triples with different inserts, but I can't remember who. You might be able to accomplish what you want by simply changing the offset of the forks (much easier to do).