Any high alpha, American hop would be a great choice for bittering... regardless of cohumulone % or FWH vs. Traditional bitter. If you want to avoid harshness, simply use less than you normally do at 60, and much more than you normally do at the 15-10-5-0-DH slots.
The main thing is to change your bittering amounts.
Instead of using 1.5 oz. at 60 to gain 60-80 IBUs...
...Do 0.75 oz. at 60 to gain 25-40 IBUs
Then don't add any more hops until about 15 minutes left in the boil.