I think in general, the approach you are using is quite sensible. In general you’d want to minimize the amount of data being transferred between LightAct and Unreal and as I understand you are already doing it by transferring only a boolean variable.
May I also clarify, are you using LightAct 3? If so, I would suggest that you switch to LightAct 4 because LightAct 3 is not being updated anymore.
I realized that the shared memory node is unavailable in lightAct 4 is seems ? I’m seeing a UE data Sender node but it is unclear how to use it. What is the right way to share live variables from LA to UE now with the new LA version?