Crankshaft balance Physics question

[west coast]

My physics question is which is a better route to go with a crank? I know if two cranks weight the same and one was externally balanced and one internally balanced you would choose the internal balanced one. So here is where you have option on balancers for the engine, internally balance you usually have more option on the weight of the balancer. Being in a performance based classes you want things as light as possibly to a point, you can always go to far on weight reduction. So for this question I am looking at total rotating weight crank + Balancer + flexplate or flywheel lets just ignore the flexplate end for now. I know they will be different weights but not enough to make up the difference in the option available in the balancer weight because the weight on the flex plate will be farther away from the crank center. Lets compare two different cranks by total weight first, is a lighter crank that is externally balanced crank weight 40lbs with a balancer of 11lbs total 51lbs. Second crank internally balanced crank weight of 50lbs and balancer that weights only 6lbs for a total of 56lbs. So which would be the choice of combination for better performance. I am looking for the science behind this to understand it. A friend of mine has a doctorate in physics and is a professor at a college I am going to ask him this question also. I am no expert at this just trying to understand. this question would apply to the big 3, GM Ford and Mopar they all have externally balance cranks that could be nuetrally balanced.