Amy, I have the Saturn Tensor 18 model you are looking at. It has worked pretty well for middle school. Shelves lift up then pull out slightly to drop into place which might be harder for lower elem students to handle. Kids tend to force them.... just pulling them up or pushing them down. I usually show all the kids the correct way, but have two stand by to help others. Keep an eye on the rubber bumpers, they tend to disappear! I've had it for 7 years and have replace a couple with cork that I slit to fit the wire shelf. I, too, put paper on the shelves if the work is smaller. It doesn't take up too much floor space for the amount of work that you can store. Like Woody said, load from the bottom up and unload the next morning from the top down. Otherwise everything on shelves that you lift up slide out the back! Storing wet, flat work is always an issue and I think some kind of rack system is a must!
It's great that you've gotten some money that you can use to invest in one! Creatively, Linda in Oregon