hello99 –
Yes, thank you for responding. Good points. My rav also holds l’halacha that the reason for ein mevatlin is because you may miscalculate. Though it would be interesting to calculate if on a normal sized piece of meat there will ever not be 60 against it, making it similar to ???? ?????? ????. But your other points preclude that anyway. Moreover, I was thinking that there is a bigger problem using 60 here, in that we are dealing with tzli.
On one thing I’m not sure though – you say that the sauce is separate from the steak; I was assuming that she wasn’t dousing it with that much that there would be any actual separate mamashus after the steak was finished done grilled, because that’s usually how it is when I grill. But if the metzius is like you, I readily agree.