I have a 3/4 Rusty Lee in my panel , took some fiddling to get it lined up and its still just a tad off . Seat base needs to be level , you might have to drill a hole in arch for it to be correct or raise the front . The thickness of floor covering will make a difference , due to the leverage a few mm will put it out. Best of luck as found it was like wrestling an octopus doing it on my own!!