The DOD Actuary provides data and spreadsheet calculators to help you determine whether the cost of SBP makes sense for your family situation. They also provide worksheets to determine if the cost of life insurance is a better value. Go to the DOD Actuary web site and select the various worksheets from the pull down menu under "Survivor Benefit Plan" on the right side of the blue bar across the top of the page.
Once in a worksheet, note the tabs at the bottom of the worksheet and work the calculator from the left tab to the right, one at a time.