I like how simple and easy it is, perhaps if you just load the website in an iFrame below for "desktop" loading, and then show images for the smaller view ports? IE: I see a lot of value in doing iPhone/mobile based viewports and providing a qrcode so we can load quickly on our own devices if wanting to test further.

Also - I've found that in some cases it's hard to tell if they want just an individual page critiqued or an entire website - perhaps something needs to be done to clarify this?