There is far more phase cancellation going on in multiple pickups and active EQ systems before your sound even leaves the bass guitar than you will ever find between 10 and 15 bass guitar drivers in similar design cabs.
Unless of course you have them wired so the cones move in opposite polarity, 180 out of phase or you are mixing ported and infinite baffle designs.
This is always a case of suck it and see, the rules are there are no rules.

I like this combination best, I think more than one amp to balance things like volume and EQ is a must though, as I need
to perfect the tone and level for the fifteens which are a lot more forward in the mid than the 10's. For overall EQ I use an SVT11P or mesa studio pre into a Lehle dual splitter.
There is however well enough dogma about this subject on this forum, to accidentally step right in a big pile of it.
