> At the moment I'm a bit confused as to how auto-window-vscroll works right
> now. I might try to dig a bit deeper at some point, and put together a
> prototype of how I think it should work.

What do you mean by "how auto-window-vscroll works"?  If you mean how
its value is taken into account, look at line-move-partial.  If you
mean anything else, please ask.