Mostly what I care about here are stats for spirits summoned by Intuitive Magicians, though I suppose Disciplined types with the Summoning Schtick may do so as well.  The TN is their highest AV+5, so maybe that takes care of it all... the assumption is that that's half skill and half stat, and they have one skill at each rating less than that.  So if you try to summon a critter and want a TN of 17 (having a skill of 17, and thinking a 50/50 chance is good enough), its highest AV will be 12.  It'll have a 6 in that stat, a 5 in another, a 4 in another, a 3 in the last (based on type), and six skills at +6, +5, +4, +3, +2, +1.

-Brian