A common issue I see in prepress is trifold brochure with panels not in position. I came up with a new approach to avoid this. I setup my template using 3 separate pages as a 3 page spread. Then I use the "Create Alternate Layout" for the smaller panel that folds inside. I wanted to upload my indd file buy get a error. Seeing is better then my explaining. Send me a PM if anyone would like to have a copy. It's simple to setup for any size sheet and very easy to layout your design. You can trust the margins. Sometimes I use it to check jobs that come in by placing PDF and can tell if the folds will work or not. The only thing to remember is to use the spread option when outputting. ...I hope this makes someones life easier.