Since Roundup Pro Max is a non selective herbicide that kills anything it is applied to, it would not be recommended to tank mix with fertilizers.
Roundup Pro Max comes in a 1.67 gallon jug.
Roundup Pro Max would not kill the tree just by applying to the leaves. It would be best to cut the palm down and apply to the stump via drilled holes if you do not want to remove it completely. Apply a 50- to 100-percent solution of this product to the freshly cut surface immediately after cutting