nut width and neck pocket / heel size on bolt on bass kits?

Hi

I don't know if this has come up on another thread but anyway:

What's the nut width and neck heel size plus other measurements on bolted 4 string bass necks? As far as I understand they are mostly the same size on different kits - whitch is reasonable considering manufacturing costs. I'm thinking about ordering the MMB-4 kit next and having short fingers and loving my 38mm jazz neck - I was wondering how much wider the standard nut would be? Or the profile of the neck?

Also I would like to know the neck pocket size for if I would like to have a thinner neck someday or custom order one with the kit - has anyone changed theirs or would any 63-64mm heel fit with little effort?

Thanks in advance

Arzi