I have a background in jewelry so I would ask first - why aren't you considering brilliant rounds? Of course it is personal preference and if you like the princess/Ascher shape better then I would suggest the Ascher over the princess because of the way it is cut. 2.00 twt definitely. A difference between the rounds and other shapes is that you can get a bigger 'bang for your dollar' with rounds over the other cuts. Mainly because with a princess/Ascher, you will need to go as high as possible in regards to color/clarity in order to achieve a decent 'sparkle' factor. Good luck and you will never regret having studs IMO.