as I have both kinds of Twins, LTDs and Bs, I can ensure you, that despite any geometrical values the frame and the setup of a B is the much better rideable bike !
Bs are more active, forward oriented.
LTDs are some kind of relaxed lean-back riding 😉
I love them, both.
The engines can be swapped (beware of different upper engine holders / valve covers),
Be aware of the B1/B2 specials like different generator setup and smaller rotor fixing screw and “front-fixed” brake caliper(s).
With electrics the difference starts and the rest of the chassis is that kind of different, that nothing fits to the other version.
Different brakes, wheels, forks, yokes, swing arms, frames. Especially the rear brake actuation is a nightmare to convert.
Close to impossible 😉
CSR is another different beast !
Other wheels, other front brake and fork. Some LTD parts fit the CSR, but it is incompatible to the Bs as well.
BTW: Sometimes standing between my Twins, I think, if there is a Z750LTD and a Yamaha XS650, they have about the same degree of compability to each other (except the engine) than a LTD and a B.
Either you are building a LTD or you are building a B !?!