Pickup selector options?

[Fang]

I have a 5 way switch with a Dimarzio Fred n/Evo 2 b. Currently it is wired for Neck humbucker, Neck single, BOTH humbuckers, bridge single, bridge humbucker.

I was curious what exactly is the purpose/tone of BOTH humbuckers for? I've never really used it to be honest, even for clean tones. I want to change either position 3 or 4 (the bridge single) to just the two inner coils, for a glassier clean tone.

[Vim Fuego]

You know, it's funny but I never use the middle single coil on it's own position 3 on my Jem, I was thinking of changing it to both humbuckers, a sound I really like on my 335 copy.
Let me know what switch you have and I'll come up with the relevant circuit for inside coils.
Jim