I was just looking at the final exit poll data from California on the GOP side. "Very conservative" voters purportedly* made up 26 percent of the electorate; they voted Romney 50, McCain 20, Huckabee 16.
"Somewhat conservative" voters made up 35 percent of the electorate; they voted McCain 43, Romney 31, Huckabee 13.
* Of course, we really don't have much way of knowing how accurate these subgroup numbers really are, especially considering the broader exit poll problems we saw (yet again) on Tuesday.
Update/Correction: Obviously, I have some confidence in such exit numbers, or I wouldn't have written a column-length analysis of them. In particular, the fact that the gap between conservative voters has been present in every prior major GOP contest makes the California numbers at least plausible (unless all the earlier numbers were way off, which is quite unlikely).