Here is how I ended up setting up my exhaust on my 336D:
I wasn't happy wit the exhaust aimed upwards, nor pointing forward, so I cut the original bracket off using a band saw, then turned it 45 degrees and re-welded it.
I then placed a 90 degree elbow on the end to redirect the exhaust away from the tractor. The exhaust is plenty pressurized to avoid the exhaust from blowing back on me, even when messing with attachments.
You'll notice it rests against the lower bracket for the canopy. This is to ensure it doesn't get broken off if I ever run over a log or something which is tall. The lowest part of the exhaust is still higher than the steering rod.
This shot shows positioning in relation to the rear tire. Even though it doesn't stick out far, the exhaust blows well clear of the rear wheel.
As a benefit, I'm still able to monitor the exhaust color without altering my seating position.
All in all, this is a really fast mod, and one which works quite well. If you are ambitious you can do as I did and buy a better quality muffler, chop the old one off the OEM elbow and weld the new one in its place. Boom! New muffler, OEM elbow, much cheaper cost. The new muffler cost me $30 at Tractor Supply (was for a Ford, if I recall)