Len, that will be the best purchase you can make for the TAC-15, really. The new version that you are getting is very tight and will not slip or move in the shaft. You will find them extremely well-built. You have to use the extreme shock end cap with this system, or you will blow the battery and circuit down the inside of the shaft upon impact.
Please call me when you get these if you have any questions at all. Not difficult once you understand how they work, but sometimes walking people through it seems to help. Installing the ESEC is very important. It is also very important to take the field point out while the glue sets, and do not install the circuit for at least 24 hours or the vapors on the glue will cover the circuit and kill it. Trust me in this one, I know because I did just that.
Once you get the system installed and you complete the steps, prepare to be amazed. If you like to track your arrows over long ranges and see POI, this is the only system that will work with the TAC-15 shafts. You have bought the best of the best and you are going to have fun.
I will be doing some long range testing and video soon, and these nocks will be key to that video. I am waiting on my Aerojig to arrive (which is from Firenock as well) so I can fletch the aerovane II's on my shafts perfectly. That way I can tune my TAC-15 with the two vane set up and Firenocks. I am also waiting on a larger Spyderweb 2.5 target so that I can shoot longer distances without losing a shaft that might have gone off target a bit.
I think you are going to like what you are getting. For me there is no other way to shoot the TAC-15 now. Your old black nocks will look like kids toys junk after you get these in. You know that the mold PSE is using is 25 years old right? PSE's nocks are terrible, and the Firenocks fixes that perfectly. Top quality product right there.