How to redirect back to the form after submit on iframe embedded form

I have a form embedded in a product listing as an iframe. If a customer needs to submit personalization for more than 1 letter (they want to order multiples), what is the best way to take them back to the start of the form after clicking submit (and having it stay in the iframe)? I can put a question on the form, that says "Do you need to submit personalization for another letter" and if yes is clicked, it can redirect to the form again, but will it stay in the iframe? Or I can put a link to the form on the thank you page, and have it say, "To submit another form, click here", but will it stay in the iframe or open in a new browser?

Also, I noticed that the form is cut off on mobile devices, can I fix this somehow? Can I make it automatically adjust for mobile devices?

Edit: I made the form responsive and I think that every filed is showing in mobile now. Would still like to know if the redirects will stay in the iframe though. :)

If you want to redirect to the same page URL after submitting the form, you can also set the custom Thank You URL redirect of the form to the origin URL.. 

Example, set your form submit URL to this...

http://legendaryletters.com/#!/*Hogwarts-Acceptance-Letter/p/64685218/category=19054005

User guide: Redirecting-Users-to-a-Different-Page

Hope this help. Please let us know if this did not work for you.