You could save Triggering unit and Last created unit into variables and use them.
You could save Key(Triggering unit) into a variable.
You could save Key(Picked unit) into a variable.
You should not do this every 0.03 seconds:
-
(R_RidersGroup is empty) Equal to False
Do the check only after you remove units from the group.
-
Animation - Change (Triggering unit) flying height to 90.00 at 1000000000.00
-> at 0.
The dummies don't need invulnerability ability, they have Locust.
Maybe you could adjust the turn speed of the unit, since the horse moves so quickly when turning.
Tough it is an ultimate, could you think of something that could be affected by the level of the ability? Infinity + 1 life bonus