My 855 has the JD style turnbuckles.
Had to choke them up to minimum length to take the sway out of Cat 1
(26" wide) attachments and draw bar.
You won't get all the sway out. You have to have enough play to be able to hook up and unhook implements.
The attaching points on the Yanmar arms may not be at the same point on the arms made for JD. You may need custom restraints. (chains)
Center the attachment behind the tractor. Measure distance center to center of attaching bolts. Make it even on both sides. Cut chain length and attaching hardware as close to this length as you can.
Good luck
Wyo