I have a player trying to use Tactician along with Twin Laser Turret. He wants to apply the stress from Tactician with both attacks from TLT.

Will stress be applied once or twice?

TLT makes two separate attacks, skipping only the "Declare Target" step. So according to the current rules, Tactician is triggered twice.

I have a player trying to use Tactician along with Twin Laser Turret. He wants to apply the stress from Tactician with both attacks from TLT.

Will stress be applied once or twice?

Seconded. Tactician is 'after attacking' so it triggers off each attack of TLT.

Yeah it's different to R3A2. It only works once for the stressbot because that works when declaring a target. Tactician works off an attack. So 2 stress with tactician, only one for R3A2.

I have a player trying to use Tactician along with Twin Laser Turret. He wants to apply the stress from Tactician with both attacks from TLT.

Will stress be applied once or twice?

Twice. But don't forget that it only works at R2 and inside the TLT ship's firing arc (printed on the base).