Does the job

my main reason to use this plugin was a page with over 5000 words was getting exceedingly slow to edit – this page requires frequent additions. I broke the content into two pages and used:
“Include content directly” and “You can specify an id or a class which specify the content area that should be included.”

On a one page layout I now have a “read more” link to open a div – inside the div is the iFrame – auto height working perfectly