Congratulations!.. Schecters are great value! But are you sure you really need to "upgrade" the pups?.. Was considering changing the DDes. humbuckers on my Schecter Corsair, but found out my money was best wasted elsewhere.
A mix of tron and hb for neck and bridge sounds ideal by the way, a hbs in neck position can get excessively "dark" and muddied if you ask me... I have no experience with Filtertrons, but – like you – imagine them to be in the P90 neighborhood... which is an ecellent place to be!
Anyway, if you want to try out different options, you should try out GFS pups (on Ebay)... They do all sorts of clones and crossbreeds, and sound great (have a couple of their P90's in a cheap Epi, which rival the one in my SG jnr.)... and don't be fooled by the price, cause they're dirt cheap!
(e)