And I do want to clarify that I'm NOT using the "complete" ORBS list, but only the verified open relays.

ORBS also has a mode where it can reject mail from servers that it was unable to test (from the principle of "if you're blocking ORBS from testing you, then you've got something to hide and are not to be trusted").

Currently, I am NOT using that, but only "real verified open relays".

D