LOL dude, yes 120x36x27 is perfect but there is a lot to consider. I definitely don't have the space in length for that and the cost is significantly more.
I have the space, just can't bend the tank to bring into the basement, so 7' max it had to be.
Hah, you guys are hilarious!
Thank you
My current tank is 6ft in length and I have 2 MP40s which seems like overkill. 2 MP60s not enough?
It's not just length, its also width and height. A single pump in a 6' x 18" tank is enough to push one way. Make the tank 36" wide and you're looking at 2+ to cover, make it even wider and you need multiples to cover the area. The fact that you're doing fish only make is much easier but also depends on rock scape as @jda already mentioned.
4+ perhaps, but you'd run them high.
I have experienced the Tunze 6255 on my own tank and it's just crazy how much water it pushes. The guy who took one off my hands confirmed that its way stronger then the MP60s he used until then.
Completely up to you. One can always add more powerheads, should they be needed.
You haven't mentioned your budget so its hard to recommend stuff.
If you're doing this on minimum dime, if that can even be said about tank of your desired dimensions then what @jda recommended might be the way to go. I assumed that people who setup something on this scale have proper budget for what I consider proper equipment.