thank you for providing food for thought. Since watchmaker is a framework, you may implement the described hybrid grouping genetic algorithm inside the framework.
The concerns stated in the paper are valid, a GA with naive encoding seems not really that good.
I guess since 1996 more people have come up with solvers for different bin packing problem complexity classes - a GA is never that efficient. You could look for greedy solvers or
an exact solver if the parameters are simple enough