Carburetor jetting

I just replaced the head on my Kawasaki Z1900 with one that had been ported and polished. It is now running smooth at idle, but will only ride with the choke on, and boggs when I get on the throttle. I have aftermarket Mikuni 34 flat slides on it with large k&N type air filters. Any suggestions on which way I should go with the jetting? Larger or smaller? And should I raise or lower the needle jet at all? Any help on this matter would be greatly appreciated.
Thanks! Tony

If it only runs better with the choke on, the carbs are definitely too lean. I would raise your needles (drop the clips) and go up on your mains. I cant really tell you how high to put the needles or jet sizes that is your call considering you can tell better than me exactly how lean it is. but I would definitely head that direction