sensor ground and splices

Im lost on how to wire the sensor ground of 5V source to multiple sensors. I understand that they sensors can share this common connections, but how to figure out my wiring needs as far as the splice. For example, lets say I'm wiring up 4 sensors on one common ground, how do I calculate the wire size for the 4-1 splice or vice versa for 5V reference?

Because the 5v reference is going to sensors which draw minimal/no current wire size isn't hugely important. Poor connections causing voltage drop is the bigger issue.

Generally if I have one 5v wire (say 20-22g in size) coming out of an ECU, I will use a crimp joint and splice this out to the required amount of wires I need. Generally the same size (20-22g).

I will also do the same with sensor grounds/ground out form the ecu. In these cases I am also against solder joiner the wires as this can cause issues later in life with poor connections and voltage drop.

I will also use the same size ground wires as I do 5V

So I'm wondering now how do you all do your ground for the coils with a concentric twist? Do you ground all the way at to the bulk head connector then to engine ground? Or straight from cool to engine ground?