The Rock-It, which is virtually the same as the Ideal EZ Lift, the Covermate Easy and the Cover-Up simply stands the folded cover up next to the side of the spa. A short spa with a large cover will leave quite a bit of cover exposed.
The other thing to consider is how far above the spa a users eyes actually are. For many people, especially if they're sitting reclined in the spa, their eye level may only be 4" above the edge of the spa.