Scooped, are you kidding me? Mark's are more middy than Rectos. But yes, recto's are a little easier to use in a band, they naturally have a good bit of upper mids, but you can definitely get a Mark to cut against a recto, no problem.
You coulda tried cranking the presence up high on the IV, dropping the 6600 a bit and raising the 2200, then of course there's always that 750 slider, have it as high as you can handle it. That usually does the trick. Also, if you want a bit more of a up front in your face kinda tone with a IV, try pulling the presence out... it shifts the upper frequencies and lowers the low end a bit (you can comphensate with the 80hz slider). Doing this gives it a bit more of a cutting tone, and you just gotta keep fucking with the dials until it's right. I've used IV's with rectos before and actually had a really good blend with the two amps as their mids sit in different spots, but they sound huge together. You always gotta compromise though in a two guitarist band.