Yeah, I think MDD should be the focus of any intraday system. That value translates to 1 unit of risk. How much are you getting for that 1 unit? How do you go forward for 1 unit risk in terms of $ account value and leverage. MDD should be directly proportional to intraday leverage. Say over 10 years your average return is 20% and your max DD is 5%. That's a very good ratio IMO. Suppose you're returning 50% per year, but your DD is 50%. This is not a system I'd feel comfy about as it tells me that long term sustainability is suspect; e.g. suppose you see 2 50% DD's in a row. Per anything adaptive; nothing complex really. I use the VIX as a guide to position sizing, but that's about it.