Responsive Icons

Experimenting with icon designed at different sizes. Let's call them responsive for now.

I decided for sizes 16x16, 32x32 and 64x64, but now seeing how the complexity of some symbols require more lines, I'm hesitating to optimise them for 24x24, 48x48 and 96x96.

What do you think, are people still often using 16x16 or 24x24 is becoming more often used? The latter sequence would ease my job for sure. :)