Got a tape measure and tried it out. Worked great, except I cut up my fingers pretty badly (couldn't stop, must have done it more than 20 times 'till the first shim broke). Need to figure out some material to cover the edges of the shim with. Duct tape might work (like in the photos

).
Also, I have an ink cartridge like the one shown in the photo, but it is the wrong one for my printer, and it's opened, so I don't think it's returnable. It is still full of ink, would this be a problem in trying to get the necessary metal part out?
Maybe I should go to a local Office Max and see if I can buy some of the used cartridges they collect to send back . . . Think they would sell me some?