Heptane works, like hexane. Naphtha is a mix of hydrocarbons like pentane, hexane, heptane, octane, etc (different brands/producers of naphtha may use different amounts of these fractions). The name is given by the amount of carbons, so 5 carbons is pentane, 6 is hexane, 7 heptane, etc. The higher it goes, the higher the boiling point is, the longer it takes to evap.
If you get just one of the fractions, like heptane, then it dissolves DMT but not too much, and its quite selective it doesnt dissolve much else like plant impurities (which is why its great re-x solvent). If you have a mixture of hydrocarbons like naphtha, it usually will dissolve DMT a bit better because it's like the different hydrocarbons "complement" in a way.
But you can still get good yield with heptane if you go heavy on the NaOH, and do warm pulls, with long, thorough mixing, and many pulls.
You can also look into limonene or xylene/toluene which will dissolve even more DMT (and some plant impurities and a tiny bit of other alkaloids), but you have to salt them out (check BLAB tek for example on the limonene salting part).
And yeah, n-heptane is the same as heptane