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I would think that with a coil tapped (am I getting confused? theres no difference between a coil tap and a coil split is there? if so I'd appreciate a correction)

There is a difference. Coil splitting is pretty straightforward. You remove one of the coils of a humbucker from the circuit. This leaves you with simply the other coil.
Unfortunately, many guitarists incorrectly use the term "coil tap" in place of the term "coil split". Tapping is altogether different. In fact, tapping usually applies to single coil pickups. Tapping involves placing an extra lead on a pickup's windings somewhere before the last coil. In this way, if some sort of switch is employed, the player can opt for the full lead to achieve the full "output" of the pickup. Or, if desired, the player can select the "tapped" lead and select a lower output. This is often done with overwound pickups to allow the player to select a more vintage (at least not overwound anyway!) tone.


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THAT said as well, I'd rewire for series/parallel switching and not coil splitting...parallel wiring puts it back to single coil tone but like the 2 and 4 positions on a [modern] strat, you don't have hum. And go for higher inductance 450s if you are certain you want to have the coil switching. A lower inductance 450 would offer relatively little with the switching.

Also be aware that coil splitting will yield a single coil (it may not sound so great) that has half the inductance of the original humbucker (assuming equal inductance for each coil). Thus, a 6.4 henry humbucker will split to either of 2 3.2 henry single coils. It also defeats the hum-cancelling!
Switching to parallel, will QUARTER the inductance. Thus, a 6.4 henry series humbucker will be 1.6 henry in parallel mode. Also, the hum-cancelling is preserved.