SPOILER Geographical Time Travel?

I seem to recall in one of the later books in the series that the worlds of the shadowgates are posited to either be
A) All geographically Mirrored
or B) The same world, at different and vastly separated points in time.

personally i think the second option is more fun/interesting, but I can't decide how would be a fun way to PROVE it in universe.

We have access to at least 2 worlds, 3 or more if some issues are dealt with but for this thinking we'll stick with the two.

IF the worlds are the same one at different times, How would you go about trying to prove that? It seems the easier of the two ideas to prove imo, and my thoughts are thus;

PLAN A) Plant Evidence; pick a different spot in either world, ie in world 1 at the base of Mountain A and in world 2 at the base of Mountain B. Dig a massive hole, 30 or 40 feet deep, at each spot and bury a Large stone or metal carving or statue or something with similar longevity. Go to the alternate spots in the different worlds and see if either object is still there. Dig waaay bigger holes in case things have moved around in the possible interim.

PLAN B) Father Tree Sapling; He made one once, perhaps you could convince him again? this assumes a lot, ie that father tree is willing to make 2 more saplings for a potentially meaningless test. Plant one tree a mile north of the gate in world 1, and the other a mile south of the gate in world 2. Go back and forth between worlds to see which god tree matured and showed up??? aren't his saplings supposed to live a million years or something?

I dunno, what are your thoughts? How can we test this?