Can a substack become the mainstack and the mainstack become its substack?

[Tom Glod]

Hi Geniuses,

I have a rather complicated application which I put on a mainstack with
many cards etc.

I now realize I need a splash stack so that I can set the script of my
application stack and its cards (for version control purposes).

Is there a way to turn my mainstack into a substack? so that the first
stack that loads is not my main application stack?

Is there another way of accomplishing the same thing? I want to load
scripts on startup from text files.

Thanks,

Tom