2 150's on a 72 inch tank? That's MORE than enough flow even for an SPS dominated tank. What makes you think you need more flow? How do the corals look? If you're looking for a tsunami inside the tank you're not going to get it with gyres. They are the kings of indirect flow and in my mind that's what makes them superior to vortech. I just wish they had a fraction of the durability and ease of cleaning the vortechs do.
My 96x30x24 has an MP60 on one side and a gyre 150 on the other. SPS near the gyre are amazing with great PE...sps on the MP60 have peeling flesh in areas facing the powerhead.
I am willing to bet you have more than enough flow.