I cast large conicals. I don't like a bottom pour for the big stuff. When I went to a ladle the bullets gained weight by about 3 to 4 grains. That means the mould was not filling out as well as it needed to. The accuracy of the bullets also got better with the bullets filling out better. I tried to get the mould hotter and the lead hotter but I never got the fill out I wanted. What was happening was the nozzle would start to slowly plug. As it started to plug the lead was cooling down as it entered the mould. The bigger the bullet the farther it had to fall.
I have pin pointed the hardness I need for my bullets with my hardness tester. I add enough lead shot to bump it up just a pinch like from 5 BHN to 6 or close to 7 BHN. The tin in the mix helps to homogenize the mix and I don't need to flux at all when making bullets. I do that when I first make the ingots.
Lastly the bottom pour pots always drip. If it were me I would order a ladle pot in the 20 pound range. Ron