I just thought of a much better way to do this...
I'm an idiot for not thinking of this earlier..
Just add custom params to your Formit call and access them via:
$customParam=$scriptProperties['customParam'];
If you have multiple formit calls on the same page... This does seem to bug out and fill in EVERY form with the last item you loop through (if in a loop).
Now I wonder if there is anyway to establish an id per formit call to avoid this?