oh, right. weston wouldn't start because it made me add myself to the weston-launch group, which meant i had to log out and back in, which unset the XDG_RUNTIME_DIR variable it depends on, which caused it to silently fail.
so i set that again, and it noisily froze instead.
however: success! i finally figured out wayfire, and it seems to work! enough that i could get a terminal up, at any rate, which is pretty much 90% of the way there
and it seems to have started an X server automagically... and one that seems to have much better performance than the standard one; glmark2-es2 returns a score of 240 on X, but 608 under wayfire! which is as well, because glmark2-es2-wayland just crashes on startup...