Re: HS combination SSL-5 or SSL-5 rwrp
Even if splitting but no cover, still get the SSL-5.
Also, because it produces a lot of output in the neck position, I'd go with a hotter than vintage pickup in the bridge. The Custom should work just fine.
If you plan on splitting, I think the slug coil sounds better, so going with the standard wind/polarity will mean no additional work required for hum-cancellation.