I would get the 2 1100's, they use a lot less watts than the 1500's, and only a little more watts than the 820's. It is a much wider water stream that comes out of them, so you don't see the direct current like on the smaller direct power heads, but you do get much better overall flow. You could easily even go with the 2 820's and you would still be pusing 29 times your tanks water volume and the 820's are smaller than the 1100's.
Just be carefull though, they don't like to start back up after a power outage, even a quick one where the power goes off for a second or two and then back on. I have 2 Seio's and 2 MJ 900's in my tank, so incase of a power outage, the MaxiJet 900's kick right back on with no problem which keeps some movement in case I am at work still.