Here's some bullets from a mold I made today. I could make it work but everything had to be just right, with the pot temperature way low, and a leisurely casting pace. This would have been much easier to cast with wheelweight, plus wheelweight would cost less, plus heat treated wheelweight usually shoots as well as any other alloy.
Many of us relied on the Lyman cast bullet manual as our "bible" when we were learning to cast. The Lyman manual recommends the use of medium hard alloys like Lyman #2. The Lyman manual suggests that tin is a cure for all your casting problems. That thinking dates back 100 years when tin was cheap, hardness testers were scarce, and a 250 gr. 44 was considered a real heavyweight. The medium hard alloys -- like WW/lino blends, Lyman #2, and 91-3-6 -- are delightful for smaller bullets, especially in aluminum molds, but wheelweight is a better choice for big bore bullets.
Consider that if you cut a mold for wheelweight, and then later decide to use a harder alloy, the diameter will be larger -- assuming you can avoid heat shrink -- and tha\'s usually OK. However, if you cut a mold for a hard alloy, and then later decide to use wheelweight, the diameter will be smaller, which is usually not OK.
If I only had one alloy, it would be wheelweight.