With that in mind I suggest, if you're married, to put more money into the spouse's Roth IRA that's the oldest more than in the one who's youngest, at least on the years you don't have enough money in your budget to contribute the annual max for both of you ($6K per person if under 50, $7K per person if 50 or over). Then when you're sure the oldest person's Roth IRA will be enough to live on after that person is 59.5 years old, put more emphasis on the younger person's Roth IRA from then on in case the Dims do add RMD's to them. The younger age not only makes it years longer before the RMD's kick in, but also when both spouses are old enough to do the RMD's the younger age will require less to be withdrawn (because the calculation is age based).
Interesting you mentioned that...I just today called my broker to move some of my Roth IRA money out of poorly performing mutual funds. The strategy of a married couple is an interesting one but my girlfriend and I have not gotten to the point of discussing marriage.
The company I work for has an excellent 401k fortunately, I was told by a banker and my financial advisor. The company matches contributions very well. Of course this money has not been taxed yet.
You sound like either an independent business owner, a broker, a financial advisor or just someone who is good with money. Thanks.