Your camera is built for EF-S lenses, but EF lenses will work just fine. It's going the other way (trying to use EF-S lenses on a full-frame EF-mount camera) that's fraught with danger. And unless you are shooting things that are less than three inches on the longest side, a 1:2 "half-macro" lens will work just fine.

The reason we kept hammering on about using a macro lens is because they are usually very good at making sure that rectangles remain rectangles -- they are corrected for rectilinearity, and usually don't have barrel (bulging) or pincushion (pinching) distortion that you can find without really accurate measuring devices. Zooms almost always have one or the other kind of distortion (and often both, one at each end of the zoom range). If you're taking pictures of "stuff" in the real world, you don't often notice a small amount of barrel or pincushion distortion, but when you are shooting rectangles it'll be apparent.

Macros also tend to have very flat planes of focus (I mentioned that before) so you can set the aperture for the best sharpness the lens can offer and don't have to worry about depth of field. (With some lenses, you'd need to focus so that a circle of the artwork about 1/3 to 1/2 of the way out from the center is in sharp focus, then stop the lens down until the center and the corners appear to be in focus as well.)

A zoom lens that is both well-corrected for geometric distortion and has a very flat field is going to be pricey (and price alone is no guarantee -- read any technical lens reviews you can find online). A good fixed-length (prime) lens is going to be a lot easier to find at a digestible price point.

If you are not shooting the works in situ, then a copy table/stand will help a lot with the workflow. A commercial copy stand can be expensive, but if you're handy at all (or know somebody who is) then building a version that is better than what's commercially available isn't too terribly difficult or expensive. I can send you plans for one if you email me (put a period between my first and last names and send it to Gmail).

<aside>I really need to post some of the DIY stuff I've created on a website sometime. When you build the stuff that you can build, you can save many thousands of dollars. I figure that I paid for my RZ67 and a couple of lenses with money I didn't spend on other gear.</aside>