How thick is the glass? that might be a limiting factor, i think the 10's only go to 3/8", while the 20's and 40's go to 3/4"
I am sure u will be fine with two MP10s they move more water then you would think.Just purchased a MP10 for my 46g bow when it's turned all the way up no matter what mode it's in it bends my seawhip on the opposite side of the tank 36" away..
Good choice, i have an MP 20 and love it. Although, if your aquarium is near silent, like mine, you will be able to hear when the mp20 ramps up. Its not loud, but you can notice it.