King, several years ago, Steve Milton installed his own brand of choke tubes in a 10-bore Zabala that I had shortened from 32" to 26". You can't even tell that there are tubes in the barrels because they are not notched like the majority of others. Rather, the choke wrench is a tapered cylinder, like a Morse taper, and relies on friction to remove/install the tubes. They throw great patterns and I have had no problems whatsoever with them. Les Paul, who lives only about a mile from my home, also does excellent work, but expect to wait 3 to 4 times the time quoted to complete the job!
