How to crop & print specific sizes in Aperture

I have a project I am working on where I need to make a series of prints that are flush-mounted onto boards that are 2.25"x5". I want to take images from my Aperture library, crop the long and skinny portion from them them, and print them out on my Inkjet printer (single prints on 4x6's on my Canon 6220 for tests, but I am going to want to print multiple-up prints on 5x7 paper once I get going as I need 10-20 copies of each print). I started by cropping (using the Custom feature) and then using a 4x6 preset in the printer dialog with the image size set to 2.25x5. I, of course, have run into the issue that the crop tool does not crop by inches, but rather pixels, and only in certain aspect ratios. I have tried making an export preset, as some suggested, but that only works if the image is the right size to begin with. By chance, some of my prints are exactly the right size, but mostly they are a bit short or wide...

How do I make a template or crop guide so that I can crop-out the portion of my image that I want, keeping it in the correct aspect of 2.25x5, and then print it out at the exact size? And then how will I do this as a multiple print job on a single piece of 5x7 paper? Do I need to figure out how many pixels a 2.25x5 print will be? Can I set a custom aspect somehow? I know in PS there is the ability to set the "canvas Size" and work the image into that, but I don't have PS on this machine. I have Pages to work with as well, but no Illustrator or InDesign apps or skills. Ideas?

Thanks!