Some Planar Science Stuff

OK, this is some basic stuff I've been using in my comic for the Planescape setting. I made a lot of it up, being the ignorant sort , so I'm just curious how close I am to the more "canon" material. So feedback is appreciated!

(from http://www.planescapecomic.com/About.html)
Theoretical Planescape!
What follows are some theories of Planescape that may appear in the comic, but not in any official material. Since this page has been used as a basic guide to Planescape (thanks!), I guess these could be considered to be house rules.

Prime Material Planes?
It is argued by some that the Prime Material Plane should actually be the Prime Material Planes (plural), but evidence suggests that this is merely an illusion from misreading the true relationship between stars and planets. If there are other dimensional planes, they likely do not share the same outer planes, but have their own Sigil, their own Outlands, etc.

Planar Connections

As you can see, the picture shows the Prime Material Plane as the sky above the Outlands. However, the Outlands is not actually an outer plane, thus justifying this view. This also shows the location of Sigil as being the center of all existence, so I like it. Also note that the blue looking sky above the visible Outer Planes is NOT the Prime Material, but rather leakage from those planes into the astral, intensifying the closer you get.

The Makeup of the Multiverse
Since the Planes are often described as spheres within each other, some different theories crop up about how they actually link up. It is known that Sigil is the center of the Multiverse, and, since the Outlands is directly below it, then it follows that the Outlands is next in line. There things get a bit hazy. The Outer Planes are visible from the Outlands, and, theoretically, so is the Prime Material. But which is actually on the outside of the great sphere, the Outer Planes or the Prime Material? In order for things to make the most sense, I would argue that the Prime Material is the outermost layer of the sphere, and is actually the only plane that is indeed infinite.

The Astral Plane
I see the astral plane as more than just a connection between the planes, it is a shield that prevents them from leaking into each other.

Finite Matter
Under this theory, the only infinite in the Multiverse is void. That is, unoccupied, empty space. This abounds in the Prime Material, it should in the other planes as well (well, possibly. See the Makeup of the Multiverse, above). Thus, even though each of the outer planes is supposed to be infinite, the amount of liveable space is finite. Whether this applies to the inner planes (as the building blocks of all matter), is up for debate, but if the Law of Conservation of Matter and Energy applies to the Multiverse the same as it does the Universe, then these planes must also be finite.