height and width need to be equal
I didn't have to skew the sprites to make the grid work
I skewed them to make them easier to draw, by being flat squares when I drew them
but you set height and width of grid to the same thing
or every other horizontal line of tiles won't be able to be in the right position
go into my isometric example and change the snapping so width is twice of half, and you'll see what I mean
but it's true, the snapping works fine, it's just visually the grid doesn't look like you'd expect it to, but one you place a tile or two, you don't need to see the grid
it's obvious where things are