I appreciate your input. 

Best, J

It much easier to put these together in Javascript, but I can do them with calculators if its quicker

 When we first added the Javascript actor, I did a series of deep tests to determine exactly this. What I found was that I could use hundreds/thousands of JS actors doing math and still have good performance... and I could also use Thousands of the Calculator actors.

I suspect you will have very similar performance either way, however; I believe a series of Calculator actors will be slightly less heavy.

Due to the nature and easy of doing this in JS, I would personally use JS. But you could easily build both and use a global to switch between the methods used.. allowing you to make a change if performance required it.

My gut feeling is that JavaScript is less work for the computer, but as @Juriaan said, I don't believe there's a "one-size-fits-all" answer in that it probably depends on the complexity of what you're doing and how you're doing it. 

@DusX might know better than me.

Happy to dive deeper with you, but I dont have an answer for you at this moment.

Will do some testing on my own and report back

It depends on the amount of replications and this is such a deep technical question that we really have to dive deep into the codebase to figure this out for you :)

For example I dont know or JavaScript code that is in memory needs to be re-initiliazed.