I've never done anything like this.
That said, before tossing semi-random amounts of crazy ingredients into MY wort, I would test out the strength/taste of each by making tea....
For example boil 6 cups of water (covered to avoid volume loss), and then add some of whatever. Pull off 1-cup samples every 10 minutes. Cool and taste. Sure the flavor will change in the beer but this might provide a rough idea.
Explore that site you provided. It gives ideas about amounts and boil lengths.
Dandelion leaves can also be used for gruit bittering (7 leaves per gallon boiled 60 minutes). I bet you could find some of those! I saw a recipe combining the dandelion with black pepper and lemon zest.
Hope this helps.