I did wonder about removing charm-type effects from the table, but the original ability description not only says charm spells are compatible, but they give a substantial (5 point) bonus to the check.Whew, have to agree with you there. Let's allow less ..explicit.. activities as you suggest. As for charm, I'm inclined to make it that charmed, dominated, suggested, otherwise mind-influenced targets don't generate any resonance, just to take it off the table. In other words, it has to be a pure Cha or Diplomacy or whatever check.
That led me to think we needed to keep enchantment spells as an option somehow.
Let's review how the potential resonance numbers look first.OK, for the reverse-engineering, maybe we should aim for points a bit higher than Reveling gets. Something like partner's Cha score plus the amount the caprine's check exceeds the DC plus a flat bonus for role-playing (perhaps) plus maybe +1 per HD that the partner has in excess of the caprine. Does that work, or is it too much?
We want the caprine to be able to accumulate enough resonance to be able to use the highest grade power (sound of death, but we don't want it to be too easy.
The current Resonance Abilities Table caps off at 101+ points, but we can always tweak the numbers:
Resonance Abilities Table
cause/remove fear, charm, sleep
mask, summon fairy folk
killer cheese, vitalize
covet, march to war
sound of death
For resonance striking methods, we have:
Cavorting: 1d6 points (3.5)
Music: success level of DC 10 Cha or DC 15 Perform.
Imbibing: success level of DC 10 Con or DC 15 Concentration.
Dancing: success level of DC 10 Dex or DC 15 Tumble/Perform.
Reveling: Highest success level of a Music/Imbibing/Dancing roll plus 5 for 2 successes or 10 for 3 successes.
A somewhat high level caprine (12th level?) could easily have, say, +20 in their resonance skills' of Perform, Tumble et cetera, especially if they used masterwork items, or magic like the heroism spell, a circlet of persuasion or their Empowerment ability.
That's an average roll of 30-31, so they would generally get about 16-17 points from each of the three single-skill methods and, maybe 22 points from Revelling.
Call it 75 points as a typical total resonance value, just enough to use covet and march to war.
If they can get 26+ from "Consorting" the caprine would have the 101+ resonance needed to access the highest level power.
That's easily achievable - indeed likely - if we use the formula you proposed: With 16+ or so from the skill success plus maybe 15 or more from the ability plus other modifiers the total is likely to be 30+.
Hmm… that feels a little too high.
How about we make it use the ability modifier of the partner rather than the raw score? The original used the Charisma "bonus" after all.
I'm also thinking we could expand the check to use either the partner's Constitution, Dexterity or Charisma modifiers (whichever is higher) for the bonus. Since we're generalizing this into other forms of passionate interactions we don't have to restrict it to Charisma only.