This might help you a little bit
in the form properties you can specify Grid x and y
however this will not change the size of the black lines and will only place dots in the grids
From what I can see
1 or 10 or higher = the normal grid
2 = 1 dot in the middle
3 = 4 dots in a square
4 = 9 dots in a square and so on
hope this helps
/locomotion