While working for Machinerylink, we had pretty good luck running rigid MacDon drapers on the 9600s, especially in wheat, where feeding "heads first" is very beneficial on a conventional cylinder machine for best threshing. It was nice having the cutter bar out front further and better view of the cutterbar. We did some trial testing of the MacDon flex draper in Nebraska pivot irrigation soybeans in 2003, but not overly impressed due to the dirt ingestion along the pivot wheel tracks. The tri-flex cutter bar could not ride up over the wheel tracks _ rigids like a true flexhead cutterbar. Things may have improved by now and some work is being done on a true "flexible cutter bar" for a draper header. But, from what I've seen, it would be difficult to match the newer 40' max-flex cutter bars harvesting soybeans on rolling or irrigated ground. Do make sure to get the right knife drive pulleys for the MacDon to match with the JD backshaft _ header drive speed. Good luck.