Grouse,
If your frizzen is bad, you will have little or no spark. Lyman has always made a great frizzen. TC frizzens, on the other hand, are highly variable. My old (pre QLA) Hawken is on its 4th frizzen. The first three TC frizzens lasted less than 100 shots each. I would send one back and they would replace it. The results were always the same. Finally, I installed a Lyman frizzen (it takes a bit of fitting) and never looked back. The frizzen on our equally old TC Pa Hunter is the original, and has never had a problem. The frizzen on our Lyman Deerstalker has also been trouble free.

As for the broken flints, I would try what is recommended above. I will say that in 35+ years, I do not recall ever breaking a frizzen in the lock when fired. I have broken a few while knapping, however.