Someone with some computer modeling savvy could investigate this. Personally, I feel there are so many parameters and many other simpler methods to increase a coils performance that screwing around with the plunger weight isn't worth my time. There's also the possibility of overdoing it. Some of the "hotter" coils in my games have resulted in broken plastics, excessive wear and other damage.
https://www.comsol.com/blogs/part-1-how-to-model-a-linear-electromagnetic-plunger/