That is tricky to answer and will depend somewhat on what life throws at us. We are natural savers, and have had years when we saved nearly 20% toward retirement alone. This reduced income is new to us, however, and we have had some recent surprise demands on our budget, so I will conservatively say at least 10% will go toward retirement. About $40k a year goes toward a combination of our day-to-day expenses and saving up for future day-to-day expenses (replacing a car, future home repair, etc.) We carry no debt except for the mortage, $78k.
After I responded i left my desk and ate lunch, and gradually realized that there were some alarm bells ringing in the background. To be clear, saving up for future 'day-to-day' expenses can't be considered part of your savings rate unless you also count spending that money later as part of your expenses.
For example, let's say you are saving up to buy a gently used car
Year 1: save $5,000
Year 2: save $5,000
Year 3: save $5,000
Year 4: spend $15,000 on the car, save nothing that year
average savings-per-year = $0.
It's great to plan for future expenses, but that's all part of your spending, not your saving.
Regarding my earlier comment - I think you've got it. Putting more money into tax-advantaged accounts will help you far more than trying to do any conversion. Let's say you and your spouse make $78k next year. If you converted $10k from a tIRA to a ROTH it would be taxed as your last-dollar-made, in this case 25%. So you'd pay $2,500 to convert and have $10k in savings. A better method is simply to put that $2,500 towards tax-advantaged accounts, giving you $12,500 in savings. When you go to withdraw that money in retirement you will be taxed on it (and taxed on a first-dollar-out basis), but you will almost certainly pay less than 25% on that money unless tax codes drastically change.