I'd also tend to go for humbuckers, besides all the other advantages mentioned, do not forget that P90s can get quite noisy.
And a set on the lower side (SM, MQ) would be better as they are usually more open, airy, sparkly than the hotter ones.
Also I would look at the source of tone, the guitar. If it's dark you could for example add an aluminium tailpiece or use brighter strings, e.g. blue steel from dean markley. BKPs are awesome, but the better the acoustic tone, the better the sound they can produce.