Yey, thanks Kosiam!
Your way of doing it is pretty much what I imagined it should look like :D
It was really clever to use the variable for locating the X's.
With that I was able to set and use a Y value as well ^^
About the problem when all 4 are the same... I've done a ton of capx where even when there is no instance left; I can Create a new one. Heck, my main project does this without any trouble -_-
There must be something else causing this problem. (Although having +1 around does solve it D: i'm confused xD)