Sprite sheet design considerations?

[Domarius]

Regarding non-power of two & 3D engines, my understanding is they will load it, but they will simply waste memory by loading them into the next power of two memory size up that fits... eg. a 64x65 texture will be loaded into a 128x128 memory space. So you still want to obey the restriction when optimising.

Ah you echoed my current thoughts about how I will approach spritesheet / tileset management. It's basically up to you to group them the way that suits your development