Your complete atlas should be 256x256 in size. With each Font Icon taking no more than 22x22(20x20 for resources) square of that. I usualy find a picture that will make a nice Font Icon then resize using Super Sampling in Paint.net to 18x18 in size and pasting that into my template, merge 2 layers(Backround onto image), then copy paste to my main Atlas. Have fun!
Edit:
If you decide to make them 22x22 in size, you will have no gaps inbetween each Font in your atlas, or you will find that as you go through your icons, they start getting offset(with a gap at 22x22), so 20x20 probably best.
Edit:
If you decide to make them 22x22 in size, you will have no gaps inbetween each Font in your atlas, or you will find that as you go through your icons, they start getting offset(with a gap at 22x22), so 20x20 probably best.
