The more the better

[Xinfu]

Situation

Someone offers to help put rice on my plate, and wants to know how much I want; I would like to have as much as possible, what are the suitable responses I can give?

[Rusty]

Besides your good example:
the more the merrier
fill 'er up
heap it on
dish it out
don't be shy

[Xinfu]

Thank you~