Marshmallow Fluff

;)Can I substitute Fluff in a recipe that calls for mini marshmallows or jet-puffed marshmallows? If so, what is the ratio–Fluff to marshmallows?

Rice Krispies Treats calls for 1-10oz pkg of reg marshmallows or 4 c of mini marshmallows. Can I substitute Fluff for the marshmallows? How much?