Short version:
With stock slide (#5), CEL-3 for an MX type 'hit' response.
BEL-2 works better for enduro type, smoother response.
If you're going to buy needles, you'll be better off getting keihin needles from sudco (800-998-3529) @ $5 each (plus S&H), than proprietary needles from kawi (like the 1173K..probably close to $20).
If the only choices you want to consider are the two you asked about, get an 1173. Not worth it, imo. But that was your question.
BTW, for future reference...when asking for jetting info be sure to state the model of your pipe for the sake of clarity. Likely yours is a K-G35? The model number is stamped on one of the mounting flanges. Also, if you have bike response issues, list the jetting you currently have..pilot, main, needle & clip (the clip positions number from the TOP ..from the blunt end) and AS position. Also the mods done to your bike..airbox, filter type, pipe, S/A, ....anything you've done.
That'll help get you better responses.
Cheers!