I'll try to get some time allocated to that - right now the machine that
I use for this effort is busy doing other things but I may be able to
free up some time on it in the next week or two.

Well that's a bitch.

Being new to phabricator.... how do I upload a diff that is off a (probably) different base rev and has my changes in it (I don't really want to "update" the existing diff, or do I?)

Definitely; I have the patch here in along with additional changes derived from my previous work running a soak test; should have some commentary and perhaps additional suggestions in a few days.

As some of you probably know I've been chasing this same general issue here: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=187594