Yeah I saw your setup during my research.. Mine will be similar in ways.. you going to leave that mount on during the summer or un bolt?
Because of the way the 200cx loader has its own kick stand i can't leave mine attached, would get in the way. So I am doing two things, the piece i got from JD will stay on year round, while the rest will quick attach. It will be a lil easier to talk to once i get some pictures..
The undercarriage frame will stay, the 300 loader also has that stand that comes down and swings underneath that area, but I made it so it just misses the mount. it's plenty high enough and will not cause ground clearance issue.
Also wanted it short so I didn't need rearward frame to structurally push off of, just pushing off the front frame mount, so far has not been a problem though we have not had much snow yet this year to really test it.
The only problem keeping that frame mount so high caused, is with the plows A-frame geometry. It is critical to have the plows frame level with the ground when the blade is down.
It really wreaks havoc not having it level, causes upward push on front end making steering difficult, prevents even contact of cutting edge when angled, makes a harsh chattering noise and vibration.
I had to mod the plow to lower the back side down, mine is still not perfectly level but it's fine now.
That's one of the mistakes you can avoid, try and get it as level as you can, without going crazy.
I did make mine to be tool-less swap between loader and frame mounted plow, though I did add 2 bolts through upper lift frame and existing holes in weight bracket.
It was not necessary as that lift frame slips over the weight bracket and stays in place under it's own weight and that of the plow when up, but it makes the whole set up that much tighter and smother that it's worth it to take the minute or so and snug up 2 nuts.
What is that JD bracket for? a plow or a blower?
Good Luck, JB.