More on pitch adjustments: (applies to the BCPP Bell-Hiller head and probably in principle to the plain CP head too)
I figured out that the physical pitch adjustment stops or limits are detemined by the sliding of the part in the rotor head called the "rotor head" up and down on the "main hub." Collective pitch changes move this rotor head thingie up and down, it carries the rotor head frame and the flybar control frame along with it. The pitch control links attach to the arms of the rotor head frame and go down to the Bell-Hiller mixers on the blade grips.
So, to start with, the pitch control links should be adjusted so that the rotor head thingie is at the center of its up-and-down travel on the center hub, when the blades are at zero pitch and the Bell-Hiller mixing levers are horizontal. I unhook the servo links from the bottom of the swashplate assembly and let the swash hang from the paddle frame control pushrods and the Bell mixer arm pushrods while making this adjustment. With the pitch gauge that should give -12 or a bit more when the rotor head is all the way at the top and +12 or a bit more when it is all the way at the bottom of its possible travel, and with the swash disconnected from the servos I can easily move the rotor head up and down to check the travel.
Now that the pitch links are set roughly, I try to set the center of the collective pitch travel with the servo arms, at the same time leveling the swash for the cyclic pitch. So here's where I unplug the motors, center the servos by selecting idle-up mode, center trims, center both sticks so the transmitter is calling for zero collective pitch. Then I set the servo arms to as close to horizontal as possible on the splines, adjust the servo link rods so that the blades have zero pitch and the swash is level. Since the servo link rods can only be adjusted by full turns I might have to go back to the pitch links at this step to fine-tune.
Now I can check the pitch in normal mode: should be about 1 degree negative at zero throttle and +12 at full throttle with the stock TX, and in idle-up it should go from -12 at low throttle to zero at half throttle to +12 at full throttle, hopefully without binding at the stops.
Here's where those of us who have added a fancy radio system have the advantage: we can set servo travel limits. The factory TX is set at the factory and I don't know how to adjust it or even if it is adjustable, so you might have to put up with a little binding at extreme travel limits.
Then I put everything back together, track the blades in the usual way by adjusting one or both of the pitch links, and "Bob's your Uncle" as they say here in the frozen north.

Now, this is the factory setup, but if I find that I need a bit more positive pitch then I increase the whole collective pitch by cranking all of the servo link rods in a full turn and re-checking the travel limits.

Now, again, if any of the parts mentioned have been replaced in a crash repair, or if the pitch links are bent even a tiny bit, the adjustments can go off a surprising amount due to variations in manufacturing, bendage, and prangery. This might be another part of the answer as to why we need to keep adjusting all these bits.

Then there are these thilly ethh theventy-five thervoth-I'm asking Santa for three HiTec HS55s.

Sorry about the long post--too much coffee, not enough batteries...

(pix are the Blade CMax Pro--new swash, CF blades, DD tail, QED fin, Spektrum RX, 2 GWS ESCs instead of the 3-in-1, a little body work on the canopy...when is a BCPP no longer a BCPP?)