Sounds as if your hooked studman !!!!!!& already remedied the most common mistake of noobs , not enuff heat (shoulda seen da mess I made of things !!)
Make sure you have it hot enuff & flux well (I use parriffin wax) so ya keep any tin in your melt .
When ya get ya some wheel weights go slow ,as most lead WW are phasing out to zinc ones & there no good for bullet casting !!!!WW & your soft stuff 50/50 should do `bout anything ya want ,except for the upper pressures in magnum loads.
How ya gonna cast , ladle or bottom pour ??????
Caliber ???, ya may wanna hang on to that soft stuff , most handgun calibers will shoot acceptable groups with soft ( dented with thumb nail , but not scratched) 10-12 bhn alloys.
Some muzzle loaders will trade ya for the soft stuff!!
Have fun , BE Safe !!!