Hi Mark.
No need to double up on grounds to the jack. (it's not that you can't, I just don't know why you'd do it - it's not common practise)

I run my bridge ground to the back of a pot which is where I typically consolidate and terminate all my individual grounds. (there are exceptions but I won't get into it now).
For the most part with passive guitar circuits, ground is ground and there are multiple ways to achieve the end result.