I spent 4 and half hours just to get to this point... it was pain. No wonder rimmed bells aren't normally made.
Some things I have found out the hard way:
-the rimmed half needs the outer edges to be a lot larger than the half sphere
>this also makes fixing any warping easier
-the rimmed half is more than likely going to be flatter or strangely shaped unless I really take my time
-you need to anneal the rimmed half way more than the cut out portion

I don't know if I'll do this again because it takes so long just to prepare it. I haven't even gotten to making the charm yet. I made it out of brass which too longer to cut out (an extra hour compared to copper)

I thought of illustrating about this but I am just out of energy