Keep in mind that you can't touch the account for 5 years after the last rollover. I got laid off in the GFC and used mortgage deductions to counter the income created by the rollovers. I spent 6 years doing serial rollovers, now I have 2 more years to wait, but I'm only 54. If you rolled piecemeal for 5 years and then had to wait 5 years to access the money... you might be dead or otherwise need the funds.
It just seems a bit late in the game, and it sounds as though you have a fair amount of complexity to deal with.
I agree, it would have been nice to do this earlier, but even through 2018 we are still in the 22% bracket. Even higher when we were working. Did not make sense to start earlier, and may not even make sense now.