Harry I haven't tried to mount them yet but have taken another look at it,I think you're right. While they will clear they will be right up against the stem with no room to fill the tire. I'm gonna go ahead and put in a notch. Sure appreciate your good eye!!!
Robert - I made some out of lead before myself. I believe I must have gone with 8" diameter. I attached them to some Simplicity cast iron weights because they are nearly flat. Biggest problem I had was drilling holes on the lead for the mounting bolts to slide thru. Talk about slow going. The dang lead would melt as you drilled it and stick to the drill bit.
Now, about that lead poisoning. I used a grill outside in the winter. That melting lead sure does smell.
Robert - well, I think I'd start over and recast them. I'd make them smaller so you can get them against the smaller inner ring part of the wheel (as I did mine) which is about 8" diameter BUT definitely measure it first