Ok...I must reread your post. I do not variate the tradesize. I noted the video that was mentioned.
1 micro contract.
ES
1 micro contract.
ES
Your assuming that gap risk only happens in overnight sessions. Market can gap down mid day, towards the beginning or end of session. Just because your data doesn’t take this into account doesn’t mean it will not happen to you in the near future or distant future or never. But it’s there.. the longer your exposed, the more likely this will come and take you out of a lot of gains you made up to that point.
And if you ignore such a risk maybe due to its unlikelihood, just know that your statistical expectation is zero and that law of large numbers will take you out.