I have one of those spent uranium faced frizzens that somebody gave me years ago in my junk box.
When those were the subject of some fierce debate in California I got into a competition with a guy that used them on his tradegun. We shot 24 targets, and I beat him. Not only for accuracy, but for reliability as well.
Half-soling a frizzen is more technical than it is often portrayed. It can effect spring balance, lock geometry, and in small locks the availability of flints.
If you are contemplating a frizzen half-sole especially on an old lock that may or may not have parts available, consider having it done by a pro.
Hungry Horse