IMO a dds is a good choice to heal for the actual damaged caused (since the basic damage can be mitigated), unless your system detects thatIf you trigger it... there is no need to use a DDS.
If you just save the amount of life just before you deal the damage and calculate the difference between the original health and new health, you have the most accurate damage calculation that exists.
Triggering the drain itself without DDS is the best IMO.
A DDS is meant to detect damage and do some stuff on the exact same moment.
In this case, you already know the moment so using a DDS can only become worse.
@BD
Target runs out of range
caster gains a new order and thus interrupting his current order
caster is silenced by any effect
target or caster is dispelled
Caster dies
When using lfh's dds, shouldnt you use his custom action?
just a few things to consider...