I didn't see@Damienga15demention using a 750 double R box ?
Info found for normal readily available 750R box is :
2.76, 2.06, 1.64, 1.4, 1.22, 1.09
(Same on all OC 750s and teapots)
Seems logical to need taller gearing for use in the 11 ?
Anyways, i actually do run a 1216 with 6 speed in real life.
I use it daily with 16x43 sprockets and gives ample and correct speed range without wheelying all the way up the gearbox like it would with the factory 15x48 setup. (Which could be cool, if you don't look at fuel prices these days )