Fitz grips were designed back in the revolver heyday of the 1930s. He made at least two designs: one for formal target shooting and one for duty or carry. I'm not that old, but guys who are tell me these were the grips to have.
Below is the only set of wood K frame duty grips I have been able to buy. I have several in N frame size, but this is it for the K frames. There are Fitz synthetic grips (called Duramite)out there, and they work fine, but are not wood.
I still have not tried a set of Spegel's grips, but hope they work as well for me as the Fitz do.
For myself, Hogue Pau Ferro's on a 4" 686 or 4" Security Six work about as well as the Fitz/M19 combo. Problem is the Hogues have a long butt that sticks out too much when I CCW them.
It has to be the way these grips fit my hands, because these Fitz absolutely seem to "reduce" recoil. Hogue Pau Ferros seem to work about as well for me.
Full power loads in this 4" M19 shoot much easier than the factory, Eagle, or some rubber grips. Most other wood grips are cut wrong for me and some actually hurt.