For anyone still following this, I solved the issues I was having.
I used lockscreen (thank you bogs - I know what you mean now), and instead of using multiple 'sends' to various buttons, I moved all the scripts inside the card. Previously I was trying to send the handlers to various card objects continuously.
I did a bit of googling about beam sync under OSX. Turning it off on OSX 10.11 has made such a drastic difference. So much so, that there was nothing I could do to slow down the original stack I'd made.
https://www.tsites.co.uk/downloads/live ... ing-v2.zip
So, I thought what can I do to actually slow this down?
Here's version 2 of the stack and it still doesn't get too choppy with all the effects on.
Hope it's helpful to someone for testing purposes.
But yeah, beam sync was the biggest difference. My whole OS feels quicker.