thank you! So, just so I understand, you can pull the money out of the IRA's at your own discretion over that 10 year span, just so that the full IRA amount is pulled out by 10 years?
Since you're interested in tax optimization, I'll point out that the law states that the IRA must be completely depleted by the end of the year in which the 10th anniversary of the date of death occurs.
So if the original IRA owner died today, the 10th anniversary of date of death would be August 6, 2030, and the deadline to empty the IRA would be December 31, 2030.
The tax planning point to note here is that this rule gives you 11 tax years to spread the withdrawals out across, not 10. Assuming the original IRA owner dies early enough in the year to enable you to take a withdrawal that first year.
My first cut plan is to take out 1/11 of the account balance the first year, 1/10 of the account balance the second year, 1/9 ... etc. However, the general rule of leveling one's taxable income to minimize taxes is a good rule, so I would probably then look ahead to see if my other sources of income were going up or down significantly during that 10 or 11 year period.
Beyond that, it's hard to give advice. People's goals and plans, risk tolerance, tax situation, other assets and liabilities vary all over the map, so what might make sense for me might not make sense for you. I think engaging a CPA who does tax planning is a good idea. Another idea is to learn Excel and how to build financial models and how to use goal seek and similar functions to see, for example, the differences between option A and option B and whether that's amount of money is negligible or not.
If I were in your shoes, I'd be inclined towards option B. I might look at spending from the inherited IRA and then using some of the taxable to pay taxes on Roth conversions between retirement and age 72 if that made sense otherwise.
I think the only other thing I'd point out is that the inherited Roth is completely tax free to you and could be used during your 10 year window to supply spending money and allow other accounts to grow untapped. At only $25K it may not be a big consideration, but it may fund a year in there somewhere. Others with larger Roths may be able to use this fact to improve their strategies.