I've had similar experience with my '97 kdx200. I replated the cylinder this winter and put in a new wiseco piston. Took care of KIPS, repacked silencer, etc. etc. etc. Bike ran fairly well, but smoked and spooged. So I started leaning it out little by little. Original jetting was 160 main and 48 pilot with needle in middle groove. I'm now down to 150 main and 42 pilot and needle lowered to #2 position (i.e. clip in 2-nd groove from top). Plug looks considerably better, and almost no smoke and no spooge after it warms up, but I still don't like off-idle transition and the air screw does not have the impact like I think it ought to, so I'm going to try a 40 pilot tonight (I don't want to mess with slide cutaway just yet). My point is that you might have to lean it out A LOT before you get there - especially if you are in Houston where temps and humidity are very high, which would require even leaner jetting than my neck of the woods. Just take it one small step at a time.
BTW, in my experience ignition timing has profound effect on things when you start getting leaner. When I initially lowered the needle the bike ran like sh*t, so I went back to the middle groove. Later I discovered that previous owner retarded timing by 1 mark. I put it back to middle "stock" position, and now it runs well with needle lowered. I also tried advancing timing by 1 mark for supposedly better low end response, and I found that my bike didn't care for it too much, so now I'm back to stock timing.
For completeness: '97 kdx200. FMF Gnarly Rev pipe, PC304 silencer, Delta Vforce reeds. I've got airbox lid in place but with snorkel removed, and I'm in New England a little above sea level with temps in the 60's and 70's. Ignition advance is on the middle mark. Yamalube 40:1. 150 main, 42 pilot, #5 slide, 1174 needle in #2 position, A/S 1.5 turns out.