Yes used to be a chain on mowers.Trying to rember now but wernt there a chain to brace on a cutter bar mower we had in the deep and distant past
wouldnt be to dificult to do and would help ,main thing is to get the geometry right i should think
And what a simple but effective thing it is too.My pottinger mounted mower has a hydraulic ram on the headstock to level up the linkage............or more to the point put the linkage at different levels, so that the mower can be made to sit level when in work position.