The intensity of red color will be less if too much water is added to the beet.
You may need more or less juice depending on the beet quality and the color the juice produces.
Use the un-used cooked beets in salad or eat as is.
You can use either Neufchatel cheese or mascarpone cheese. I was planning to use only mascarpone but ran out, so added the Neufchatel instead of making a trip to the grocery.
We are not a big fan of buttercream frosting, but if you prefer, you can use the beet juice to your favorite buttercream frosting for an all natural red buttercream frosting.