Seriously, I put in however much I think looks 'about right', and it's either enough to feed the 5000 or turns out to be a portion size akin to an overpriced Michelin restaurant who expects their diners to have stomachs the size of ants. How to know what the actual right amount is? It's just me and DH, but we sometimes entertain and sometimes want to make double quantities for lunch the next day. How do you super humans do it?!