i have the tin lizzie 18. i must start by saying that i love it! and i loved the price. it doesn't have the bells and whistles, but then neither do i.
i don't know exactly what you mean so i'll try to get it. if you want to layer it all and then put it on the quilter, you can. you would just baste a header and footer so you can attach it to the canvas header and footer that it comes with so you don't sew into them. i know this works. you would wind across the two top rollers. if you already have enough extra fabric on the top and bottom you can forget that first step.
if you mean can you put more than one on at the same time yes, you can. it works either across or down. you would use the attached tightening clamps on the sides and a piece of fabric between the two quilts in order to treat them as one.
in either case if they are already layered, you would just roll them across the top rollers. if they are not you would roll them correctly but as one.
if they are pillow-case-type that turns inside out so that you don't have to put a binding on them, you would still have to back them with a foundation so that the batting doesn't get caught in the bobbin. then you would have to put an unquilted backing on them and not see any quilting on the back. unless you do the entire quilt, with turning and all, and then roll it on. remember that you need to leave room for the quilting to come to the edge at the top and bottom. be very careful not to sew into the canvas or you will have to take those stitches out. i've had a few accidents and been sorry. i had to leave a lot of extra at the top and bottom to avoid that, so i don't know what to do with a quilt that's already been turned rightside out.
i can only think of carefuly basting an extra band of fabric there at the very edge. if you use the stretch clamps, it should be tight enough if your layers are very even with no pooches. i would still baste in this case.
chatty, right? good luck with the project. let me know how this works out, okay?
i just thought of another approach: on your regular machine, do a few rows of outline or fancy stitching, following the edge. bring that stitching in just enough to give yourself the space you need to attach to the canvas. that way, you won't have to quilt to the very edge because that part will already be done. i would still baste. i think it likely that the back will end up with creases. in the pillowcase type there's really no way to tighten the back more than the front, which is what you need to do. unless you cut the back smaller to begin with.
clear as mud, right?