Miz, I have the 35g hex. I think you should get a 750 e one (only IMO). I have that AND a 450 in my hex and it is great flow but nothings blowing away. I guess if you want lighter flow go with a set of 2 450s. But I am just thinking you might want more then that, when I turn off my 750 and just see the one 450 going it doesn't cut it. The 450 nano I think you mean is about half the size of the 750 however, I don't know if thats an issue for you or not. Good Luck!!
-Heidi