My intention is to use two 20’s or 40’s in this link https://www.accuride.com/media/4889/ss-acal4120_40_1016.pdf to help support a slide-out in a small building. The slide-out weights 1,300 lbs. The slide-out is 6 feet wide and extends past the building 29 inches. I plan to use two of these with 4 feet in between them. They will not hold the entire weight of the slide-out. They are for additional support only to help keep the slide-out from dropping ¼ inch when fully extended outward. Would this be a good application or do you recommend another product?