How do I arrange my project (Event Sheets) ?

I seem to be running into issues where the communication between layouts and events sheets is complicating things.

My current project basically has a Main event sheet which gets run first and then event sheets for each layout which individually include the main event sheet.

However I want my main event sheet to contain various utility functions that can be used anywhere but it seems that way I have arranged things I cannot do this.

For example, a function in the main event sheet called from another layout stops functioning when I switch layouts..presumably because the include gets included again in the new layout effectively resetting the main event sheet.

ANyway, this gets all very messy very quickly so I just wanted to know what is best practice.

As far as I can see, one giant event sheet with everything might be best, or are there advantages that I can get from multiple event sheets?

Or maybe the only thing broken here is that functions with waits and/or waits stop working when a layout is switched??!?

Thanks