How to diagnose a redirect loop caused by forcing SSL?

Here’s the link to the site I’m working on

http://www.texasshredderclassic.com/registration

I have two main problems

1) if i set the URL in wp-config to https://, it gives me a secure (and much slower) site. However, gravity forms still says the page is insecure, because it’s pulling content from insecure locations. Also, since the content is insecure chrome won’t display it.

2) If I force SSL on just the registration page with Better WP Security, it puts me in an infinite redirect loop (what’s happening now).

I’m under the impression that if I can fix this loop, then I’ll also have fixed my first problem because Better WP Security will force the content to load securely. Problem is, I just don’t know how to diagnose what’s happening, and how to fix it! Tried to use firebug, but the console doesn’t display any errors.

Any tips would be greatly appreciated! Thanks!