OK, I can do that in release 1.2.1 (due next week). I am also planning to externalize the eiviction queue size as well.
After thinking some more. I can also just override process (already public). Have my process call super.process(), then do my own pruning. This seems more OO, because it does not have to override an internal method such as prune. It achieves the same result, so now I don't seem a reason to override prune.