jet needle clip setting KZ550

I got my carb rebuild kit from z1 and will dig into them tomorrow. Everything's all apart, including the plugs over the idle air screws, and since I can't find anyone who knows what ultrasonic carb cleaning is up here I guess I'll be spraying & cleaning them myself. So onto the questions...

I have a US model '82 KZ550C3 with the TK(?) carbs. Since I have the rebuild kit, I'm replacing everything -- jet needle, needle jet, pilot circuit, main jet, etc. (the only bad component looked to be the float needle as all four had scoring). As I look over the rebuild kit tonight, I see that the jet needle in the new kit is the adjustable kind, whereas the one I am replacing is the US kind -- only one position. So, should I (1) not replace the jet needle, since it doesn't seem to be in bad shape, (2) replace the jet needle and place the clip at about the same location as the one I'm replacing, or (3) adjust it up or down one notch from there? The bike has never run well and I'm finally trying carbs before I give up, have already noted some anomolies while taking them down (float needle scoring and the #3 idle screw - under the plug, mind you - was over a half turn farther out than the rest).

Finally, for the life of me, I didn't find the O-ring between the needle jet and carb body below the venturi. The Clymer claims this is there for US models. Thoughts?

Thanks in advance,
Nick in MA