On my B-Line Studio frame we had to slip conduit over the takeup roller to keep it from bowing when a large quilt was loaded on it. I'm not sure what the takeup roller on an Inspira is like. On the B-Line they are 3/4 inch square tubes so we were able to slip that inside of 1" inside diameter electrical conduit (EMT). When I extended the frame to 12', we had the square pipe sticking out the ends of the 10' EMT conduit which still kept the takeup roller rigid enough to prevent bowing.
If the center is sagging and causing a bump where the rails that the carriage run on are--you'll have to think up some way to brace it. We put the screw in type leveling feet on the B-Line and that helped. Sitting the feet on something solid will help if it's sinking into carpeting.