Exporting spritesheet in a squared image

I’m creating a game in unity and I’ve created a few shaders. In order for the shaders to work properly, I need the image to be in a squared format (32x32, 64x64, … and so on). The shader uses an emission texture, so from every animation I need to export the main spritesheet as well as the “textured” one. This would be an example of it:
example_emission

I need both spritesheets to have the same frame in the same position and I need those spritesheets to have a 1:1 aspect ratio. In the current version, there’s no option for me to do so; I’ve been using the “PACKED” with fixed size, but many images in the texture are the same, and the “PACKED” option has a mandatory merge-duplicates; which mismatches the sprites between the two spritesheets.

In previous versions, there was the option of setting the size of the image, and luckily I have a previous version available in my pc, but I’d prefer if this was available in the newer version where I’ve got the scripts running :confused: .