Chuck,
I get what you were saying and I didn't say anything about penetrating a CB. There are a lot of variables that need to be looked at i.e what's the cloud base, now big are the cells, do you have a radar, how close are they to each other, are you vmc or imc etc etc. All in all I just don't believe that there is an answer to your question beyond wait for the line to pass you and then go.