I "retired" at 50. In no particular order, here are my thoughts in response to your question:
You offer a mix of numbers ($$) saved and percent moving forward. There are a few issues with this. Few FIRE savers are saving so little. My minimum goal was always to maximize the 401(k) along with 5% company match. This meant at least 20% of gross was saved. More when the company made an extra profit sharing deposit. The number wasn't higher, as we also were saving 8%+ for the kid's college account. For what it's worth, we agreed that the last thing we wanted to do was to saddle our one child with student loan debt, so part of the retire early plan was to have that set aside first.
The 4% rule. Not the right place to debate the rule itself, I'd just point out, we don't have any clue what your spending is. 4% means you need 25X your desired withdrawal each year, gross, including taxes, etc. This goes back to the percents saved. If we were saving 23% off the top, and 7% went to FICA, we were living on 70% of our income. The best advice I can give to this point is to suggest you spend 2 years and track every dollar you spend. This will give you your bottom up budget. i.e. not a constrained budget you must adhere to, but a reflection on where the money actually goes. Nice to own your home outright. How much will the roof cost to replace? (mine was $24K last year, thx for asking) The HVAC system? (4 years ago, 'only' $12K). It's easy to think "we don't do too much" but once retired, you'll have time on your hands, and it would be awful to have to turn down some nice vacations, or home redecorating. TL;DR - 25X your final real budget.
Roth is overrated. There. I said it. In 2019, the standard deduction for a couple is $24,400. The 10% tax bracket ends at $19,400. This alone is $43,800. Multiply by 25 and you have $1.1M. Now, tell me why you'd want to pay tax to deposit to Roth (either 401(k) or IRA) at today's bracket of 12/22%. Worst case, you save 'too much' pre-tax and you'll pay 12% on withdrawal. Most of my working time was spent in the 28% bracket, lower early on, and a few good years higher, but now my withdrawals are 22% tops. Some times I wish I had access to a Roth earlier (by the time they were introduced, I was already in a higher bracket), but all in all, no regrets.
Social Security Benefits - check the government website for your forecast benefit. Don't use it to calculate your retirement, just consider it a safety net. I am now 56, and my wife 63. Her SS benefit is about 1/4 of our annual budget. A bad market or a few unplanned emergencies, and I don't need to worry about breaking my 4% plan. Because in 7 years, the withdrawals drop to 3%, and 7 after that, to 2% when my SS kicks in. Also, mortgage ends in the same 7 years, that’s 15% of spending that goes away. Had I really gone crazy with the spreadsheets, retirement would have been earlier, but far riskier.
Sec 72(t) - I wrote about this on my own PF blog, it's a rule that permits early withdrawals. Tax, but no 10% penalty. It's the easy (well, paperwork) way out for the early retiree. No need to be paranoid about that 10% threat.