We have just the one Jac GK IV left and primarily use it now to mow collars and approaches . There are a few side slope cuts leaving missed grass areas because the decks will turn to right or left to much .
In my scrap pile there where some old lift frames that where perfect for the job .
Cutting the ends off leaving a little nub to weld to side of lift/pull frames.
then I put a bolt trough the topside for additional support. The operator said it was a big improvement and was able to contour his cut around the green with ease. Plus no more missed grass areas between the front and rear deck. Doesn't affect the to and fro movement just takes out a good 80 % of the side to side play .
Cutting a cleaner outline .Cutting great on slopes too now.