I've set my idle at 1200rpm give or take. Theminimum idle of 2000rpm might be caused by the pilot system just not working (a #30 PJ could do this). You're probably having to open the slide to the point that the needle jet is coming on line. I agree about the O2 meter, according to my meter I'm running rich, however if I jet the carb to where its "perfect" (14.7:1 ratio),my bike simply would not run well.

 

I originally jetted my FCR at idle based on the O2 sensor. However, after the O2 sensor said it was right, it was exhibiting all the signs of being two lean at idle, i.e., hard starting, took a long time to "warm up", etc. After some more research and learning that O2 sensors will fib to you at idle, I bumped the jets back up something more reasonable, fiddled with the fuel screw a little, and it was much happier. The O2 sensor is much better for mid to higher RPMs and I used it to basically confirm the main jet a/f report from the dyno WOT throttle setting and once calibrated from that I knew what voltage it was outputing for optimum mixture. Then used that to adjust the needle setting for low to mid-range throttle positions. It seemed to be jetted pretty well after all that, at least about as good as I could get it.