Got to join in here. Seems like whenever I read about someone using Kasenit to harden a frizzen face, they follow the directions that come with the product. Those directions weren't written with frizzen hardening in mind. I bought a lot of Kasenit when it was available (fortunately) and use it in a slightly different manner. I hold the frizzen flat, face up, using a wire coat hanger as a holder. I heat the frizzen to past red to orange, then apply a thick coating of Kasenit. I use an old fashioned blowtorch - the kind that burns Coleman fuel - as a heat source and I hold it at heat for around 30 minutes. My "soak" is determined by how long the fuel lasts in that torch. From time to time I sprinkle a bit more Kasenit on the frizzen face. For a quench. I use a mixture of two quarts very thin motor oil and a quart of transmission oil at room temperature. I make sure to swirl the frizzen around in the oil so it constantly comes in contact with fresher, cooler oil.
My son is a member of a reenactment group. I've done a number of frizzens for him and other members (and other people as well, of course) and have always had very good results. It's not unusual for those guys to fire 100 rounds or so per event. The frizzens I've hardened have and are still giving good service.
And there will be people who will say "you're doing this or that or something else completely wrong " - there always is - but my method works very well. I sometimes think that the frizzens that were casehardened are castings, not forgings or milled out of solid stock, and thus may be more porous. Not a metallurgist so just a guess. Never used Cherry Red. I've got enough Kasenit to outlast me so can't speak to Cherry Red's effectiveness.