If there's no hesitation when slowly opening then, I think the larger nozzles are worth a shot.
I'm going with Shrinker's explanation here, which I'm not sure I fully understand, but think I do.
Paraphrasing, he said that the pump shot is needed to rewet the intake manifold which evaporate with the change in pressure. Something like dew forming on surface but in reverse.
Once the throttle are modeately open, shouldn't need pump shot. The venturi's will keep fuel flowing matching airflow. The challenge is the low speed circuit which is dependent on manifold pressure.