Find a Lyman loading manual, I think #49 is the current issue but any will have what your after. They have scads of lead bullet data for most any caliber you have.
Use any cast bullet loading formulas for coated bullets as a starting point. Any properly coated slug will be able to exceed velocities usually associated to cast slugs without leading the bore so you can carefully increase performance to your preferred level of use.
If I had those bullets, i would try 10 to 15 gr of Unique.































