After mulling it over & waiting until I had time to put in a good initial effort, I've created the tag pecs_with_breasts for characters that have defined pectoral muscles underlying their breasts. I've managed to get a good start on populating the tag, but would love some other buff woman enjoyers to pitch in and help me get the tag off the ground. Wiki page is already set up with some information that will help with identification, and I'm going to make implication requests for pecs & breasts right after this.
good hunting