9×16 brochure

I’m trying to make a brochure that opens up to 9×16. This size fits perfectly into a regular long sized envelope. I’m having a bit of a problem trying to figure out where exactly to set the margins in the four panel spread. I’ve been using InDesign from CS5. When I print it out on double-sided 11×17 paper using the laser printers in the office, the images don’t align. I was expecting that and realize that I’d have to print them separately and then glue them together to get a more accurate idea. I found a website, though, that has great downloadable templates for illustrator, photoshop, indesign, and in Jpeg format to help. Here is the link: artboxprint.com / download templates

To figure out how I was folding the brochure I found this helpful visual guide from 3plains.com: