I actually pay good money for chopped roasted dandelion root from the health food shop and it does make a pretty tasty beverage. I will make my own soon like yourself, I reckon after drinking gallons of the stuff that it is best to roast it until it is almost burnt , certainly very very dry and crunchy so you can then grind it up and if you have an expresso machine put it in there, failing that boil it up with water or milk.
I don't find it makes me go to the toilet much , but I am aware that it is a good liver tonic. I have read about it and not seen any warning on taking too much but fruit bat in shades said it may become toxic if you have too much, certainly no probs for me having a bedtime cup daily for about 2 months.
Ofcourse the leaves also make a good addition to salads... Bon Appetit