Does the "Perform this attack twice ... " translate to

"Perform this attack" + "Perform this attack" i.e. 2 x "Perform"

OR

"Perform (once) this attack twice (2 times)... " i.e 1 x "Perform"

for the purpose of triggering "Perform"-effects, like Tactician.

Not entirely sure about Tactician, but R3-A2 only works once on TLT attacks.

Twice for tactician. They are 2 separate attacks against the same target just like cluster missiles.

Not entirely sure about Tactician, but R3-A2 only works once on TLT attacks.

R3-A2 only works once because he works when you declare the target, and TLT is two attacks against the same target, so you're only declaring the target once.

Any ability that triggers when you perform an attack or after you perform an attack will have two trigger opportunities with TLT or Cluster Missiles.

Thanks guys. I ruled that one correctly then.