I make a powered version and use 2 heaping tsp. I like that it is thrifty. It does not suds up.
It may not brighten whites as much but (at least for me) but then again, whites were meant for "Sunday best" in the past.
Vinegar is great for fabric softener.
I use Fels and "grate" it in a food processor. Then mix some of the borax and soda (not baking soda) and process it too to blend.