How can I find the camera viewplane size?

I am doing plans for projects I build on our lot. I need to submit these plans to the county and be able to use them for my contractor, too. I’ll be using a plug-in to give me the needed measurements and I’ve figured out how to add notes and so on. The one other thing I’m working on is an info sheet to specify my information (as the designer and owner), address, and so on. So an info sheet will look like a bit like this:

The white is actually alpha, although it doesn’t look like it. I’ve specified, in the program I use to create these sheets that the resolution is 300 DPI and the measurements are 13" x 7.5". The camera is set for 1300 x 750 resolution. The idea is I can prep one of these sheets, add all the other notes I need on it, save it, then import it as a plane. It works, except for one problem.

Notice the info sheet is the same proportion as the camera, but not the same size.

It would be a big help if I could just put the info sheet flat against the camera view port, and parent them, so the image moved with the camera, that’d be great. The problem is I can resize the image-as-a-plane to what looks like the right size, but can’t be sure I get it just right until after printing it. I had hoped the camera would have vertices I could snap the image to, but I can’t do that. And I can’t get the actual size of the camera view port or position it so I can use the 3D cursor or any set of coordinates to position and size the image so it matches the camera view port.

Is there a way to either get the actual size of the camera view port, snap a plane to the view port, or size an image to the size of the view port?

I’m also open to other ideas. The issue is this is something I’ll have to do half a dozen to a dozen times on each project, so I don’t want to have to make large amounts of changes to each info sheet to make it fit properly.