changing speakers (celestion heritage)

[matteo]

I am swapping the V30s in my two 2x12 Orange cabs with G12M and G12H Celestion Heritage.
The Heritages have to been soldered and they have two pins: one red and one black. So, to which pin do I have to chain the other speaker and to which one do I have to solder the input jacks?
V30s have two pins but they have the same colour... maybe one has the "+"...

One bonus suggestion : )
I am thinking to load one speaker with G12H (the lower one) and one with G12M (the upper one). Or is it better to load the cabs with a mix?
G12M are 20W and G12H are 30W, I use it with an OR50 head at about half volume, or without master volume with an attenuator.
What would you do?