Well there ya go, just think how purty those would have been had you added that tin.
When I started out a couple of years ago, I read, and read, and read, this, that, and the other, about what was needed to pour up the perfect bullets. This was well before I even poured my first ones up.
When I DID start, all I had was a 3/4 full bucket of VERY rusted up WW's and a couple of Lee 6 cavity molds. After smelting down those weights into clean pure WW ingots, I got busy pouring up my .452-300 RF's for the 454. It only took a few sessions to figure out that with the proper alloy temp, and a nice warmed up mold, those things would fall right out of the blocks, and shoot just wonderfully. I didn't then, nor now, worry too much about appearances as long as they were filling out and sizing properly. Besides when there leaving the muzzle ain't nobody going to give them a look see anyway.
Since then however, I have added a few different molds to the cabinet. In doing so I have found that with a couple of them I DID need a bit of tin added simply for fill out, due to the finely milled blocks. About the only other thing I have found a real need for tin has been with controlling expansion. If your pouring up HP's it is almost a must to have a balanced blend of it in your alloy, especially if your running things up over 1100fps.