Yes I think the 750 is too small...it will work but you'll be shorting yourself on power. Look at the post of my buildup- Ryan dyno'd mine with a 950 and 2 1050's and found 20 hp difference. Now I am temporarily running my old 825 Demon and it runs GREAT but is it down on power compared to what it should be? OH YEA!
Call the pro's on this board when your ready for a cam- you could get 50 different answers here and they all might be fine but you've got to pick somebody for that 1.