Camera size and RenderTexture

So I have a little setup; a plane with all my necessary materials on it, and an orthographic camera attached. I will be using ReadPixels through this camera, but I don’t exactly know how to set up the camera to match the plane so that the rendered texture will turn out perfectly. I’ve tried several different Rects, but I haven’t found one that fits well enough. Various camera variables have also been a bit wacky.

I’ve made the plane 1x1, and an orthographic camera needs to be at 0.5 size. But it still shows up in widescreen. I can’t seem to adjust the camera to match the plane exactly, regardless of my screen size.

Are there any references I can read about this specific problem?

Or perhaps someone might know a better way to manage this setup?

You could project a vector from every point on your surface ( up to the maximum supported resolution ) to an arbitrary plane representing your screen coordinates. This plane can then be crafted into a texture and displayed at the near clip plane of whatever camera type you like.