Viewing US Only Ads in iFrame?

I'm working on an email submit iframe thing for email submit offers which are only for US. When I access the page the iframe is on from the UK I get redirected to a different page and so I can't see the actual landing page to position the iframe so just the text box and submit button is visible.

I've tried so many different proxies and every one shows it positioned differently.

To anyone using this technique, what's the best way to see the actual positioning? And why are the proxies showing it on different page positions? :yield:

the best way to see it is as follows:
go create a wordpress blog and place a link to your landing page there then keep your cursor over the link in your post this will show your landing page as a screenshot.hope you understood.
wordpress.com always shows screenshot of links using snap.com.i did it with this method and it worked cool.