Hi, so I made a snap grid placement system. Basically you can set the distance of the points on the grid in 3d space. Ie, 1 or 0.5. by my custom script.
Then, when you click on the screen, you use a playmaker action to get the nearest grid point. Then place your object on that grid point (ie, force it to the grid point).
Its still early stages, but you might find it useful. I can make a video for it in the next few days if you are interested.
The grid points are made dynamically, so there is no real overhead as far as I can tell. It does not use arrays.
I am not sure this could/would work with the cutout part, but its another idea anyways