The difference is 3" obviously! Kidding aside, i prefer working with 2 identical sizes,but thats only my opinion. Working with with 2 different sizes feels unnatural to me Edit: And you don´t have to mess around with color settings and stuff if you buy 2 identical ones.
This. Along with Prince of Percia 1 Prince of Persia 2 Flash Back Fade to Black Decent 1 , 2 , 3 Hexen Heretic 1, 2 Golden Axe kid chameleon man there are soo many I've played through out my childhood and uptil now that I cant remember. =\
Yeah there's some advantages of using 2 materials on one object, but that does count as 2 draw calls. But if one material is instruction expensive, that is perferable to seperate them. You can also have 2 textures set up on one material, it just depends on what you are trying to do exactly.
Don't forget you can access your brushes by making shortcuts to the 1, 2, 3...9 keys 1) press "b" 2) Ctrl+alt + left mouse click a brush and press "1, 2, 3 up to 9 " to store your brush 3) save config regularly.