Did you mention what year the 200's are?
We've got an '05 DE 200 with the variable ignition map, running an FMF
Gold Series pipe w/ Power Core II silencer / SA. We use NGK BR8EV plugs
We ride mostly tight woods at an elevation of approx. 500 -1500 ft above sea level.
After MUCH trial and error we settled on a # 40 pilot, LTR needle / clip
in the 3rd(?) position from the bottom and a 175 main (a 172 main will also work quite well).
The bike runs clean and crisp down low and doesn't starve for fuel on top.
Note: we usually run our ignition on the "Rain" setting.