Ok I only use my RY bridge splits combined with an IT middle as I have it wired autosplit on a 5 way with HSH PU combination. I like what I get and I think it works. Still, there is one thing I recommend cause half a HB is still no SC (the more powerful and dark the PU gets the less of an issue this is, which is why the crawler rules for splits). Just in terms of winds and such it does not add up. Yet there is one thing that can lessen the difference.
Do a PRS style split and put a resistor in series with the wire coil that you send to ground (turn off). That should be the green and white wire if I recall. That way when you split the coil does not completly shut off, just turned down a lot. Like using a volume knob in switch form for only one of the two coils. This results in getting the SC character from the main coil with the other, turned down one, contributing in adding back some output, lows and taking out a tad of hum. That makes for a sound which is much closer to a real SC I find and makes the jump not as extreme.
Super easy to do as you really just need to put a resistor between the end of the green and white wire and the point where they are supposed to go in the split wiring you are going to do. PRS recommends 1k Ohm for the neck and 2k for the bridge. Works, but I am gonna next try 2 and 3 as I have my PUs also turned around so the split coils are the outer ones making stuff even brighter. Anyhow, try 1 and 2.
I hear there also is a variation using a capacitor where you donīt turn down the volume but lower the resonance peak which I will also try (hopefully) soon. Might be even better for what I want.