I was concerned with how low the rear jacks sit on mine. But after using it all year, there has only been once where it got close to hitting something and that was backing through a ditch (don't ask). I think they are close enough to the rear wheels that they aren't at too much risk for the average RV'er. I've watched them closely on speed bumps and sharp driveways and they've never been close enough to get out and look.
I would echo what others suggest - move your suspension to the lowest holes in the spring hangers to give you as much clearance as possible.
2016 Jayco Eagle HT 29.5BHDS (ordered 12/30/15, delivered 3/8/16)
2015 F-350 crew cab, short bed, 6.7L PSD, Pullrite Superglide 3300 hitch