[CR]Bullfrog products for rust removal

Has anyone tried the Bullfrog rust remover gel (as seen here: http://www.bull-frog.com/) I'm interested to know how it works for removal of rust on areas with somewhat fragile paint. Context: I recently picked up a nearly complete early 60s (I think) Legnano Gran Premio with lots of rust, although most of it is just surface rust. Here's a reference picture: http://www.flickr.com/photos/basicclode/2720486648/sizes/l/ The chrome has already cleaned up nicely.

I've really enjoyed the recent preserve/restore conversation. I've been telling myself that this will be a resuscitation. Really, that amounts to preservation, then riding. There's just too much original goodness to save and proper restoration is way out of my budget.

Thanks,
Ryan Hildebrand
Costa Mesa, California, USA