Actually, I asked that question a bit prematurely, but any answers to number 2 are still welcome-I'd like to know about any and all options.
For the record, for number 1, you can get the associated profiling with a vanilla ocamlbuild/oasis setup without any hairy plugin by doing:
ocaml
setup.ml <options options options> -tag profile
From there, just executing your program like normal will have it poop out a little gmon.out that you can work with with gprof. As far as how good it is, it's as good as gprof/gmon because that's what it is behind the scenes.