Unless I'm missing something at 59.5 I pull as much money as I can each year from IRA/401K, still keep my self in a reasonable tax bracket and roll it all to my ROTH IRA. Yes I pay taxes on withdraws but I move it to an account that earns tax free from that point. If I can get a large chunk moved by 65 Medicare age, I'll no longer have earnings on anything the Roth earns other than dividends. So this should not effect my MAGI thus helping me keep below the thresholds you have posted.
I believe you are correct, as rules sit now, but watch for the conversion rules to change as I feel like there are going to be more limits, restrictions, etc., to clamp back door shut. For myself, I do not plan to convert as I get queasy thinking about paying the tax ahead of time, money I'd rather not part with before forced. Eventual tax free is worth less to me than bird in hand shelter. Pre-tax 401k a very nice thing to have during career.
I plan to live off of mostly 401k>IRA divs, maybe taxable portfolio divs, too, and leave Roth to last running money. At RMD time, I'd prefer to move IRA companies in kind to taxable, first move right before Dec 31 the year I am 70 to decrease the value upon which RMD is calc'd.
I can pay IRA withdrawal taxes from divs I already had coming in plus divs from the companies removed from shelter. Moved companies quit contributing to the growth of IRA, also.
Since my accounts are with same brokerage, it shouldn't be a big deal, move as many companies out of tax shelter as needed to meet min in the rest of years, last bit maybe wait for late Dec to get as close as possible to designing your own next RMD (heh, in theory...).
More valuable to me than cash is keeping my money paying me. Taking a hunk from my pocket to incur advance tax bill is not my style, no stomach for it. I absolutely understand how it is a good strategy for others, but I'm ok with pay as you taxation while I deplete the IRA.