I didn't understand your problem completely.

What's the cost function which needs to be optimized?

Basically you have to qualify which kind of mathematical optimization problem you have.°

Finding the best load for a restricted number of machines is a classical school book problem.

> Any ideas, modules recs, or links greatly appreciated...

As a starter see Discrete_optimization

Probably you are already done with Linear programming and Simplex_algorithm

°) best with equations