I don't really consider "rationalist" to mean "a person who is rational," but rather "a person who studies in the methods of rationality." My question was intended to demonstrate the silliness in breaking rationalists up into fractional classes by pointing out that there's no actual reference class to compare them to.

More rational, less rational, yes. More of a rationalist, less of a rationalist, no. The idea is as silly to me as "half a biologist." A rationalist is a qualitative, not quantitative, descriptor.

[Edited to eliminate some redundant redundancy.]