I vote for marris otter. Did that in the past with 60% rye. Accentuates the bread notes. If you're looking for a crisp pale, just make sure to mash low. Just my two cents...
I would mash at 148 if I wanted a very fermentable wort (crisp=dry generally speaking), the lower you mash (I'd never mash below 145-146, and that was only once), the longer you need to mash. At 148 I always mash 90 minutes.
What other specialty malt are you using? I agree if you are using just rye and 2 row, go with marris otter 2 row. But if you are bringing in any crystal or biscuit etc, go with american 2 row. Especially if the rye percentage of the grist is low (like < 25-35%).