Most of the places that get you during low water are not even named rapids (with the exception of a few). An unloaded cat is no big deal, especially if he's following someone knowledgeable.
If your really worried, go on face book and find Middle Fork of the Salmon River Guiding Professionals. These kids are running 22' loaded sweep boats and drift boats at super low levels, and the good ones rarely park. Find out who's deadheading that day, or just chat them up on their page. They love talking about low water lines.