Just some general thoughts on tin and lead alloy for hand gun bullets
I've used wheel weight for many years, straight with no other component added. They gave me 1000 fps loads in any hand gun without leading so long as the bullet fit the goove dia. of the barrel in auto's, and/or the cylinder throats of revolvers. In actuality, bullets need to be .001" larger than groove dia. or throat size. I added finger tip sized chunks of tin only when I couldn't get a fully heated mold to throw fully filled out bullets. This usually solved the problem, and the tin in my supply lasted almost indefinitely.
As wheel weights became harder to find, I've taken to diluting it with stick on pure lead weight, up to 50% with good, no leading results. 1000 fps is no problem for softer bullets like this.
For harder bullets, pushed beyond 1000 fps, I water quench my bullets, dropping them directly into a 5 gallon diaper pail. This significantly hardens them, and I've used them up to 1600 fps, with a gas check and though a Marlin .44 Magnum, micro-groove, Model 336.
Currently, my local tire shop, where I buy ALL MY TIRES, saves all their wheel weights for me, and I buy them for $20 per 100 lbs. From that I get about 70 lbs of usable lead alloy weights. As you know, lead alloy weights are going away...legislated out of existance...so get what you can NOW. At $20 per 100 lbs, my .44's cost me less than 1/3 cent apiece if you discount the cost of my casting equipment. As an example, I just cast 1000 .357 158 gr LSWC's which paid for the cost of a new Lyman mold.
Hope this all helps...save the tin or trade some of it off for a lot of wheel weights...a lb. of tin for 50 lbs. of WW's is about what I'd do.