Phil,
I have the 10, 12 and 14 0.8 triple and double sets some with all three but do manage with a starter and bottoming in some.
Not sure why you are going for the 11 and 13
I know some in the states had gone for the "odd sizes" but I believe that it was just to be different. (elitism) Don't get me wrong there are argument for both, but I don't agree with them.. But that's me.
Just may need to think about selling the drills for each tap size as well as they will be odd sizes that are not in the standard sets.