For me, I rarely, if ever, have used the middle pickup, but I like the #2 position. It would be perfect to wire it so that #3 is HH, but 2 & 4 is single HB etc.
The "Morse"-switch to add the bridge hummer to ervery position.
Norm has it on his silo.
Wire it like on the Morse (the switch with the 2 wires under the left singlecoil)