The bad thing about getting lead from pewter is you have no idea what % you have. I found a source several year ago for tin bulion, 99.9% pure, cheapest investment for sure tin alloy I ever made. I have a supply of over 1000 pounds in pure lead ingots from fork truck counterwieghts, then I have over 150 lbs of lynotype from an old printing operation. All I use, and every time my mixture will come out exactly to my recipie.
I use a lot of pure lead tin alloy for low speed under 1000 fps bullets in HP's, the tin does the main job of allowing the soft lead to fill out and make sharp corners in the mold, but also aids in toughness to keep the bullets from tearing apart at the mushroom. It aid in elasticity as well as consistent wieght by filling the entire cavity of the mold, even in harder alloys.
This is more than I will ever need for casting anymore. I only shoot cast in my handguns, in fact I won't wast money on jackets in a handgun as they are poor options for power, accuracy, and I'm lazy, jackets requier cleaning the barrel to keep them accurate, cast DOES NOT!
I also learned years ago, wheel weights are the most contaminated source of alloy, and the easiest way to destroy a batch of wwalloy there is today. Most ww today are not ww alloy, but contaminated with zinc! Zinc will destroy any alloy you have for casting accurate, non fouling alloys.
For the past 20 or more years I mix my own, I prefer just under #2 alloy, and can run over 1600 fps in my revolvers, from heavy 475L, 454 Cassul, 45 Colt, 357 mag, 327 Federal, and 32 S&W Long. Having enough of each alloy I can blend my alloys consistently to match any alloy I use time after time.
I don't need a hardness tester, or an analyzer to know what works for me, but that is what casting is all about, making an alloy that works and being able to repeat it over and over.
The biggest mistake most make with revolver bullets, is making to hard af an alloy. Second is being able to repeat their alloy. Be very careful smelting those ww into ingots, and like I said before, keep the lynotype alloy separate.