If am investing 80$ in Gambling, then I do understand that if I am loosing very fast and I have already lost more than 90%, I am not going to invest any more money in there since I know my luck is not on my side as well, so what I would do is to use all that amount that I do have in there and would not attempt to further add any more on the same day or even on consecutive days, for me threshold does not depend on the Money that I invest in Gambling but it does depend on how much I have lost, what Percentage have I lost, which is usually, 90% but my anxiety starts calling me at 50% usually.
Your plan is good . If someone lose his deposit and he is addicted to gambling and keeps depositing there to recover his loss. Then it will take a more horrible form for him and he will face a bigger kind of losses. So it is better to stop gamble when you loss your 70-80% of first deposit