Mark,
I agree with the points you make. Another thing to consider is that the variability between carbon tubes in terms of weight and stiffness can be quite a bit less than the current alumunum hardware. This is assuming you standardize on one builder using identical prepreg material and layup schedule. Variation in the weights of the Marstrom prepreg platsorms run in the neighboorhood of several ounces for a 284 pound weight. So, we are talking in the nieghborhood of .1% weight variation. This is also the type of results obtained with aerospace composite parts. I suspect this is less than the current tolerance on the aluminum sticks. The goal is to to make sticks with enough similarity that no one has an incentive to shop for multiple masts optimized for crew or wearhet conditions. To do this with composite tubes you almost have to commit to a single builder because even if material an tooling are specified the layup (individual ply orientations) can be manipulated to produce tubes with a wide range pf properties even though they weigh and look the same. Thus, you would also have to specify and control layup schedule. Not a hard thing with one builder but becomes more difficult with multiple builders.

Kevin