A. The way that person measured pull ratios was wrong from a very basic geometry standpoint. You can't just measure the pivot distances and ignore the pivot offset, and you can't pull the lever to the bar. That's why he got such ridiculously different results with the identical 4700 and 6700 levers.
B. We know all those road levers and road brakes are compatible. People have been using them in all sorts of combinations for decades.
C. Double pivots were introduced with zero changes to the previous levers. Dura Ace, Ultegra and Campy brought out dual pivots on groups where the levers were exactly the same as the previous year's single pivot lever.

Dual pivot and single pivot brakes work differently and pull cable in slightly different manners. Neither of them pull cable linearly. Brand X and Y levers AND calipers pull cables slightly differently. They also have different shapes that interact with your hand differently. All this produces different lever feels, but none of which affect the ability to set the brakes at a normal brake pad gap and be able to stop with a 'normal' amount of lever travel.


You took a rather innocent series of tests and came away with a conclusion no one else did - the small variations in road equipment = incompatibility. This conclusion is totally unsupported by the evidence or actual use. You made it up.