Lets add some more complication that the rod builder takes into consideration. One guy has huge hands , the other small hands. The reel seat size changes.
Some rods , usually fast action rods , have quite a taper , some rods have much less taper. The reel seat changes to accomodate the taper.
Some guys want the reel seat 18 inches from the butt , some want it 32 inches from the but. The reel seat changes. All these things have to be accomodated by the custom builder. I use two systems to mount the reel seats. One involves the use of a very liquid epoxy system (Flexcoat rodbond) that allows for good filling of thin gaps between the reel seat and the blank. Tthe next uses a very viscous epoxy (Kardohl) system , more like putty than liquid , which I use when there is a big gap to fill. The methods used to shim the seat and apply the epoxy vary greatly between the two systems.
Some people don't use cork tape. They use real cork or just neoprene. Some people don't even want a continuous handle , just some handle material in a couple of small lengths down from the reel seat with the rest a bare blank. A reel seat , if properly applied , could be used without any grip material at all and it should not come loose.
Anyway , maybe the methods for doing this stuff is best left up to the collective knowledge of the people who build thousands of rods amongst them and discuss this stuff freely in person and at rod building seminars and on the rod building forums. Also remember that most of the rodbuilders are also pretty good fisherman.
My last comment is about the cheap shots at guys who feel its worth the money to pay for art work. just cause they think its worth paying extra for a nice looking design , doesn't mean they are ignorant about the functional aspects of the rod. Some of the best fisherman I make rods for insist on all black rods. That's not because an all black rod fishes any better or worse than a rod with a fancy butt wrap. Someone who specifies an all black rod is in his own way , making a "fashion statement". Some people choose a navy blue suit and some people choose a black suit. It doesn't mean that the guy who chooses the blue suit has less awareness than the guy who chooses the black suit that the primary purpose of the suit is to cover his butt crack.
It sounds to me like KMB is a little defensive and trying to justify why he uses a factory rod that has repeatedly had a reel seat come loose vs getting a custom rod built. His way of justifying his own medeocre choice is to run down the custom rod and the people who would choose to spent the money to get the very best rods available. By running down the custom rod , he hopes to make his factory rod look like the best choice. To a truly knowledgeable fisherman , that trick just doesn't work!