Give me a strategy for getting to 500% multiplier and/or donut farming?

What do you even mean by maximizing your percentage? Having only items with a multiplier?
Optimum for what?
You keep telling was that you know better, and that sometime in the future you'll "explain". Instead of telling us that, start explaining what do you mean at least. It would be a better use of everyone's time. Otherwise this is just spam, without adding anything to the topic at hand.