Jim had already posted seedings in this post:
http://www.predsff.com/forums/showthread.php?t=16944
Personally, I prefer the way you determined it, but only because this is the way we do it in SAC'd and all other leagues I am in that use the same tie-breakers.
But however you all have been doing it is fine by me. I don't think we had this dilemma last year?