I got it to work with both the Google viewer as well as the Office viewer. Here are the codes:
For Office:
<iframe src='https://view.officeapps.live.com/op/embed.aspx?src=Current cell's File's File's URL' width='100%' height='100%' frameborder='0'</iframe>
For Google:
<iframe width="100%" height="800" frameborder="0" src="http://docs.google.com/gview?url=http:Current cell's File's File's URL&embedded=true"></iframe>
With Google I had to add the http part as the amazon link doesnt have the http by default. I had to ad the ‘URL’ part to the dynamic part too for it to work. Please note that my string says ‘File’ but that is the way I named my Thing.
The only downside is that these viewers do not seem to support images so I would have to create something else for that if I want to show them in the same RG. Perhaps a filter based on the file extension?