Find a local shop that knows carburetors and have them tune it on a dyno, would probably cost $200-300 (depending on how long it takes them and their hourly rate) but it should run great after that.
Another solution would be to ditch the carburetor and go with fuel injection:
That particular kit is California legal (I noticed you were in California). It is a bit expensive but in cold weather it will start perfectly and it will run the way it should all the time. The way they drive improves 10 fold.
If you order, you can use our BJ100 promo code for $100 off!