I'd add a little bit of distortion. I got a Sansamp DI pedal for this specific purpose.
I went to our storage unit this last weekend and one of the bands we share a space with were talking... The guitarist told the bassist he needs to get a fuzz pedal because he heard a friend of his with one and he punched thru like crazy.
I said "WOAH WOAH WOAH slow down skipper! You don't need that, you need a touch of distortion". I was glad to help because I was going thru the same situation a couple of months before this with my current band with me not punching thru two high gain guitarists with my 4X10 and 260W SWR head. The Sansamp pushed me thru and changed my tone in a good way. I didn't even have to add a lot of drive on it. Just enough to give it a nice sound and punch thru the frequencies.
For the record, this guy plays a 150watt peavey amp with a 1X15.
I went home, got my pedal, plugged it up for him and adjusted the settings a bit and he was diggin it. One song in and the drummer stops and gets mad and says "Dude, you gotta move your **** into another position man. You're ALL that I can hear".
The bassist looks at me and says "Dude I've been trying to get them to say that for a year. How much you want for this pedal!?!"
Anyways, that's my opinion on your situation.
And for the record, here's the thread of me asking if adding a 1X15 would help me get thru the mix and then posting the results after the Sansamp. You actually posted it in it, but maybe it'll enlighten you on some options.
4X10, considering adding a 15 for more low end. Need a little input.
