My Lyman #49 manuals and my alloy calculator list Linotype as 84% Lead,4% Tin,12 % Antimony. For a 20 lb. pot my alloy mix calculator basically confirms what hornady states 50% Pure Lead and 50% Lino give you a air cooled BHN of 14.7.
I changed the percentages in my calculator according to your Lyman handbook numbers and the BHN for air cooled bullets comes out to 13.44. This is just an educated guess based on known numbers your alloy content may vary. Testing your own bullets will confirm what your final BHN will be but you should be in the ball park.