How to select central square?

Whant to continue question in this post: Problem which i can not solve for 7 months

I use Instance Tiling for do some cool stuff, but stragle with idea how to select central square of mask, that Instance Tiling produce in way that compatible with Tiled Build

Mask every time looks like this:

By using Select height you may select central square like this, but mask is repeatable. So you can not select only central - each time you will select all copyes of it

So i have no idea how to make it work only with central one

I want to move placement of Instance Tiling by hand, without distrotion - so it reduce amount of possible solutions

Did fix it by using this technic: 🤔 Why composite type do not work with Distortion type? - #4 by Tomatiy

just want to comment if one liitle guy will read this after 99999 years