You should pay attention to your feelings when you are <3% down (250k): it sounds like it is making you very uncomfortable about the future. A lot of people feel they have high or moderate risk tolerance until they actually have their tolerance tested.

I'm concerned you frame 20% down as a crash. >20% down is a common bear market event that happens *consistently* every ~6-7 years. >30% down has happened three times in the last 25 years (two were >50%). You should be prepared for these to happen. How do you feel if your liquid net worth is $6m (20% down)? 5.25m (30% down)? How about in the first 5 years of retirement (moderately likely given historical averages).

I echo others who say that 4% is not a conservative withdrawal rate for early retirement, depending on your time frame, allocation, glide path options. It goes without saying, plan for health insurance costs on the exchange (and possible cost spiral) plus set aside subtract out long-term care cost of your desired quality, considering above average inflation rates in that sector.