I just played the guitar and compared how I thought the full humbucking sound compared to the split coil sound thru the Fender DRRI. The full humbucking sounded super good at all pickup switch settings and it sounded really great overdriven with a bad monkey pedal and a carbon copy delay pedal into the same amp. When I pulled up on the tone knob, splitting the coils, the apparent volume immediately dropped and the the sound seemed thinner; with only half the pickup working I would expect this. When I compared the sound by turning down the volume to a level on the full humbucking setting that was equal to the volume of the split coil sound, I noticed that, again, the full humbucking still sounded more full and powerful. The split coil sound seemed still thin but less driven sounding, to the point where, to my ear, the split coil sound was more like that of an amplified acoustic guitar sound and chords sounded more like ones played on an acoustic, especially on the bridge pickup which was brighter than the neck pickup. The middle and neck switch positions seemed to exhibit the same differences to me, with the neck split coil sounding more full than the bridge split coil sound, but still thin.

Played clean, as well as overdriven, the full humbucking sound was way more interesting and satisfying to my ear; full of great overtones and powerful density of the sound. I like the full humbucker sound and think it sounds nicer to me for rock and blues.

I really like the sound of my strats and telecasters and they don't sound anything like the split coil sound of the '59 and Custom 5. My strats and teles definitely can roar and rip the place up, and they sound good thru all my amps. I haven't developed a taste for noiseless single coils that much. A screaming single coil thru a decent amp sounds great to me.

I also really like my Les Pauls and other full humbucking guitars, and they definitely rock the house. I like the noiseless aspect and the powerfulness of them, plus the fullness of the sound and overtones. There is no sound to me like a roaring real nice humbucker thru a nice clean amp, an overdriven one, or an ultra high gain one with lots of controlled feedback shaking the walls.

I am more likely to use a real nice telecaster with Seymour Duncan alnico II pro pickups to get an awesome single coil sound, than I am to split the coil on any guitar that I have that has coil splitting; and to my ear, I will get a way better sound with the tele than I will with the split coil.

So, for me, I would rather have a single coil guitar and a humbucking guitar than try to get the sound of both out of a split coil guitar.

From my point of view, which is limited to me alone, I think you are still definitely doing great with the SG and the SD '59 and Custom 5; no matter how you wire them up. You will always have what I think are "top notch" full humbuckers in that SG, and it should sound super fantastic thru a decent amp.

What amp do you have, by the way? A lot of times you can really improve your rig by upgrading your amp, because there is no substitute for a decent amp.