Ballast choices

[f350ctd]

I'm weighing, pun intended, the options to add ballast to a 253 I am purchasing. Currently it has the base model steel hubs with 8 loop rims. I don't know if it has fluid in the tires but the tires are in need of replacement so now is a good time to exploring options. I've had experience with cacl and rusted rims in the past and it seems add-on wheel weights are hard to find. I'm wondering how much is to be gained by swapping in the cast iron wheel hubs that are common on the larger models - 165, 255, etc. I know different rims will be required. How much do the centers weigh for the 28" wheel?
I've also considered liquid ballast in the form of WWF and RV antifreeze.
Thoughts? Pro's and con's?
Danny