I'm confident that my SZR720 should have enough space in the control cavity for the circuit board, but it's far more of a simple question on my mind.

The guitar is currently H-H config, but I was thinking of purchasing the FSK-401, which comes with a bridge humbucker and a single coil driver. Is it possible to get something to mount the single coil in a humbucker route or would I be better off getting a humbucker driver and another humbucker (probably a BKP Nailbomb) for the bridge?

Quote by Kensai
Please, I eat gays for breakfast...

Quote by Kensai
I must be even further in the closet then
i think the fernandes sustainer kit comes with both a humbucker and singlecoil, so you will have one that will fit your guitar
Get a Sustainiac: http://www.sustainiac.com It allows you to use whatever bridge pickup you want and you can choose the driver size. You can also customize the controls. Plus, support at Sustainiac is probably among the best ever.
I'm currently working on a system to generate MIDI from the motion of a guitar. More info coming soon.