I am not sure about the radius but Loys Toys has a long web page about the properties of Peco turnouts on their website. Here is a link: http://www.loystoys.com/peco/about-turnouts.html David
More info on Peco: http://www.sodigi.com/Peco_Track.htm I have seen a table with all the data you are looking for. I cannot locate it right now. Seems like it was in some type of track design website.
Thanks for all the replys. I looked at that page slim and I found it kind of confusing. I couldn't tell if anything there was a #2 switch. I'm very impressed that peco has them though. They make for much smaller HO layouts for those of us who may need a smaller layout. Definately for switching areas you can squeeze lots more in. I don't really want to mention the kind of radius I'm thinking of playing around with because it will make you all cringe.