carter yf rebuild question

got a question about my rebuild
Bought a kit and it came with two different size pump balls a small and a big one and retainer. my question is which size do i use? Also there is a small rod above the ball in the diagram but my kit dosent have one do i need it?

http://oldcarmanualproject.com/manuals/Carbs/Carter/YF/pages/Image19_jpg.htm

i have included a link to a site that shows an exploded view

thanks