If you are running a single taper needle and a 168 main, you may very well be too lean. Your slide on an '00 is a #6 stock. The #6.5 came about in '01. On my 380 I ran 45p 1369N needle (#3), 170 main> in the summer. On my 380 I wasn't on the main much. If your bike is running good with the current set-up I don't think I would worry about the #7. At my altitude here (4500'-8000') the #7 is a must.
The Delta II works well on all KTM 2-strokes, it is worth the money. Since you are riding woods I would recommend you getting an arrestor vs. just a silencer. The FMF TCII is not much louder than stock. However, if you already have the PC on, Oh well!
Dan is right on his Delta advice! You 'normally' drop both the pilot and main. However, with that lean main (168), I would leave it or go up to a 170.
Good LucK & remember jetting is trial an error. Just take on step at a time, not two, one!
:D