Your project looks fine for me, and works perfect with resizing the page. Unfortunately the issue with the left and right reticles looking different to the top and bottom is still happening though. It’s really weird that the top and bottom have the same resolution as each other and the left and right have a completely different one even though they are all the same. It’s like they are linked in some way.
This is the code I use to re-size the actual crosshair, although I do not think this makes a difference really. If you manually change the size of the reticles in the editor the same thing happens. In some sizes the left and right glitch out, and others the top and bottom glitch out.
this.crosshair.setLocalScale(this.crosshair_size, this.crosshair_size, 1);
I also did the same as you and created a custom reticle using paint and used that as a texture but even then it happens again…
Here is a quick screen cap of the crosshair (small) without an outline:
As you can see top and bottom look really bad compared to left and right, even though I followed all your tips. This is really weird.