The only experience I have with floating leafs is on dirt ovals. Although I did have a brainstorming session with a guy about just such a deal in the 70s. Binding was one of the concerns we discussed. There probably be no bind in the rear half of the spring due to shackle or slider. The front half is where you could get some binding. If there is some arch that could eliminate some of it, how ever any bind would come from the difference in ark between the front half of the ladder bar and the length of the front half. If you had a shackle or slider on both ends of the spring, It should have no bind or stiffening of rate at the farther reaches of travel. If the ladder bar and the front spring mounting hole are the same length and parallel you would have no bind.
Just a by the way deal. the leaf spring floating was used on the right side and it was not floating on the left side, on the dirt oval. With the aid of a well arched left spring and a spring/ coil snubber it induces rear steer to aid in corners. Some Modifieds are still using a similar set up. The left spring lengthen or shortens wheel base on that side and the snubber decides how much.