I am doing a monster bubble popper with multiple numbers of columns, from easy to hard. So on an iPad at 5 columns, the sprites are very large. On an iPhone at 10 columns they are quite small. I am using artwork at about 300 x 300 pixels, with no anti-aliasing in the originals, and a small number of colors in each sprite. So far the sprites look surprisingly good on all devices. I am using world coordinates and adjusting the sprite sizes on the fly, and the default target height of 640.
Since the game is always in portrait mode, I suppose I should choose a target height of 960 to get best results on iPhone, and its probably close enough to 1024 for iPad. Then for retina displays and Android devices with more pixels I could use 1920.
So far I am getting identical results with either a perspective camera at 78 or an ortho camera at 8. I presume those will change if I change the target height, no problem. Do you have any suggestions on how to proceed, or am I on the right track?