recommended version of rrdtool 1.2 for Hobbit 4.2

I'm thinking of upgrading my production Hobbit server to rrdtool 1.2 when Hobbit 4.2 is released. Is there a preferred version of rrdtool that I should use, or just grab the latest (1.2.15)? Also, has anyone had success with building the RPM on RHEL3 using the spec file provided with the tarball?

THanks, Tom