Check out this link from EQ clerics which incorporates Lucy...
http://www.eqclerics.org/forums/arch...p?t-13110.html
The basics of what I'm seeing is 1 point of agro per point of damage healed is probably what the mechanic is during the current time period assuming its the same on p99 as it was on live. (or 2 points of agro for 3 healed, with CH capped at some number possibly depending on which post you believe and when changes were instituted).
However, for sure, certain spells have more/less agro than others. Heals over time have greatly reduced agro. Heals that have other things mixed in like buffs/cures have increased agro. Rune type spells have massive agro if a mob is in range/engaged when it lands. It also seems to me that at some point casting time had an effect, ie the longer the cast, the less agro it generated per point healed.
All that is only partially helpful, and for sure you can't look at the agro a tank generates (for which we truly can assign a pretty legitimate number for swings/procs/nukes/clicks) in quite the same way you can heal agro because we just don't have good numbers for the heals. You can look at Lucy, but those numbers are liable to reflect what the spells agro is currently on Live, not what it is on p99.
Heal agro is something that you need to learn by "feel." ANY heal that lands right on a pull is going to bring you agro. Any heal on a puller is very dangerous unless you're certain they are FD or already cleared agro somehow. Heal agro is generally greater on fast heals than it is on slow heals, Repeatedly casting divine light will be tons more agro than a couple of CH's. Group heals are a butt-ton of agro and you should expect to have agro after a group CH, try to use a smaller group heal or even heroic bond as HB seems to carry less agro even if casted repeatedly.