Wow, 200 is cold for a whippin OS. I've had to tune one OS mill at 330 degrees F.. But let me tell you, IT FLIES! I have written OS on numerous ocassions and they always insist on the same thing, "Tune your engine until it has no more gain in performance. Whatever temp provides the best performance is what you want to run.". That is their standard answer. And with the warranty on most, you can replace it up to 2 years. Keep in mind, they condoned running at 360 deg. F. on an OS CVX Hyper .15.
Because your exhaust is pointed down, your spent fuel naturally has a place to escape. If what pours out seem excessive AND your temps are as low as 200, well, i would have to go with leaning it out.
I sometimes do this by
set HSN to 'stock after break-in' needle setting (typically a quarter turn in from break-in setting)
set LSN to factory break in setting
fire it up and set the idle to accomodate needle settings
run a half tank
take temp
This will be your baseline - write it down and keep it near your fuel bottle at all times (i put mine in a ziploc bag)
Start leaning and keep leaning until you see that there is no more performance gain. Watch your temps the whole process. If your hitting 350 - you may want to go back a little and run there)
Smoke is always a good indicator, but, a honeybrown piston and sleeve along with good compression is the true indication of an engines wear and tear. I just now started recording compression settings on a mill at the time of purchase.
Still trying to establish the best oiling process for all mills. That will just take some time to do right.
Anyhow, hope this helps.
I blab too much..........