Wire gages are a tough proposition. Gramps is correct that insulation has no bearing on the gage. Gage is actually a measurement of the weight in oz per sq foot. For wire, there are also various "standards" mostly depending on the material the wire is made of. There is the United States Steel Wire Gage (steel wire), American or Brown & Shart Wire Gage (non-ferrous steel wire, except music wire), British Imperial or English Legal Standard Wire Gage. All have different wire diameters listed gor any particular "gage".
I usually use the American gages for non-ferrous gage for copper wire. For .016" diameter 26 gage would be the correct assumption. The chart you are using looks like the correct one to use. The diameter with insulation should be somewhat larger and would be the dimension you need to use to convert to the scale ignition wire size. This can vary with different brands of wire.
The stranded wire gage reflects the overall diameter of the stranded bundle and the diameter of the individual wires (44 gage) is considerably smaller than the 26 gage detail master wire. There is really no equivalent diameter comparing stranded to single strand wire. The outside diameter listed as .016" should be the same overall as the detail master since both list the diameter, but remember that the stranded wire is the diameter of the whole package, not the individual wires.
Hope I didn't confuse you too much. Your basic assumptions are correct but the wires from the stranded wire would be more suitable for "dashboard" wiring than ignition wire .. unless the OD of the insulation matches, which I would doubt. Now I'M confused.. eheh. The only real way to tell is to have it in your hands under your micrometer!