Here's how I do it (note: I have blown 2 accounts in the past 20 years, but had no MM).
When I am going well, having a good month for example, I will risk up to 5% per trade, pushing the pedal so to speak. I make about a half dozen trades per day. Usually the risk is much lower however. I average around 2.5%
When I am not going well, I cut back on size and risk no more than 2%. This is adjusted each day. For example, given a hypo 100k acct, I'd risk no more than 2k per trade. If I had a shitty day, the next would be 2% risk of a lower number. Therefor, you'd be losing less and less each day, theoretically its impossible to reach zero, but at 10k, I'd say the acct is blown.
In actuality, I wouldn't even risk the 2% if things were crappy, it would end up being 1 contract trades until I was going good again. Or I'd go on vacation and take a break.
Jay