A Magic: the Gathering deck is seldom larger than 60 cards, around 40% of which are lands.
I have cards and effects that "mill" my opponent, meaning it takes cards from the top of their deck and places them in the discard pile. Some of these effects mill a certain number of cards, and others mill until they mill a land card (or multiple land cards), then they stop. At times, both of those effects happen "at once", and I get to decide the order in which they happen. I have other cards that get better the more cards are in their discard pile.
My question is this: given that I can see how many lands are on the field (and thus deduce approximately how many lands are left), is there a way for me to determine which has the larger benefit: either milling a certain number or milling until they reach a (certain number of) land(s)? Does this depend on the number of cards being milled or on the number of lands to be reached before milling stops, or both, or is there even any way to determine?