I would make up a lifetime spread sheet. This takes the rest of your life, year by year and you put in all your income and all your expenses. Include of course investments and taxes and health insurance. You can tack in car replacement, furnace replacement, new roof in the years they're expected.
I would be VERY careful about expecting that 4% is fine forever. 4% was the Trinity study number used for 30 years. If you plan to die at 75, then you might be fine. Otherwise, no.
On the bright side, if you have at least 10 years of social security earnings, you'll get something from social security. So in that lifetime spread sheet, chalk up some income, when each of you plan to take it.
Also, are you planning to do "fun" jobs when you leave your big dollar jobs? If so, that is income. Whether you decide to take advantage of your credit cards and sell spots for Tradeline sales or drive for Uber (hint, my Tradeline sales last year were much higher than the average Uber driver and I didn't put a single mile of wear on my car), you can bring in some money. That also helps as you'd be able to potentially put in Roth money.
I originally built my lifetime spread sheet to show my wife what she'd have when I kick the bucket. It helped me get through lumpy things like $300k for one son's college and the learning disabled school for the other son at $100k.