Comparison: complexity measures vs. security
Not sure what you are trying to do but are you not approaching it the wrong way? 

NIST already recommends algoorithms/ciphers for use in their environments. This means they have vetted these and are deemed secure. Now you want performance as well. So use openssl and see which of the algorithms are of acceptable performance to you. Like you said choose key lengths that provide the same level security when comparing different algorithms. That way your performance numbers will be comparable.

Also I wouldn't try to go beyond any algorithms NIST recommends. For example AES is good for any application. There is no reason to use or try twofish. There are enough ways to shoot yourself in the foot just by using AES itself. Stick to one and that way even if you are creating some recommendations for your users/employees its less complicated.

Hope that helps.