It's unclear to me from looking at the generator and reading tooltips whether it's more efficient or not to feed the oil-based generator different types of oil fluids. Is the oil-based generator working faster or is more productive with petroleum compared to crude oil? What about heavy oil or light oil?

Edit: It should be noted I'm still on version 1.0 of the mod which I believe is before you migrated the generator to a different mod.

Yes, the different fluids have their own fuel value.

            eName = "light-oil",
            fuelValue = "0.95MJ",
            fuelEmissionsMultipler = 1.5

            eName = "crude-oil",
            fuelValue = "0.45MJ",
            fuelEmissionsMultipler = 4

            eName = "heavy-oil",
            fuelValue = "0.57MJ",
            fuelEmissionsMultipler = 3

            eName = "petroleum-gas",
            fuelValue = "1.1MJ",
            fuelEmissionsMultipler = 2

            name = "napalm",
            emissionsMultiplier = 2.5,
            fuelValue = "0.85MJ",