There are so many moving parts here, you may want to see a financial planner. Creating taxable income by doing Roth conversions will affect your medicare premiums and the taxability of social security (when you take it). You are going to have some withdrawals already for living expenses, so you will have to plan carefully so that the extra you take out for conversion does not put you into too high a tax bracket.
Just as an example, if you are single and need $40,000 per year after tax to live, you will already be withdrawing $50,000 and pay 12% tax on everything over $15,000. If you withdraw another $40K for conversion, that will be taxed at 22%. However, if we suppose you receive $1000 per month in SS benefit, then at age 70 you would only need to withdraw $16,000 per year to make ends meet, which will almost be tax-free, or taxed at 10% or 15% instead of paying 22% now.
Also, I learned this when my mother developed dementia. If you need to go into a nursing home, you must be "poor" for Medicaid to pick up the cost. That means you get to keep $3000 and a car, and everything else goes to the government. You turn over your assets, your pension and SS benefit, and only then, Medicaid will pick up the remainder. But, as long as you turn over the RMD of your traditional IRA to the nursing home, you get to keep the principal of the IRA to use for whatever you want, or leave it to your kids. But because Roth IRAs have no RMD, you have to turn over the entire amount before you get your nursing home covered. It's years or decades away, but it's something to be aware of. There's probably an argument that you need a well balanced portfolio of pre-tax assets, Roth assets, and non-protected investments. good luck.
