The amount of oxidizer on a molar basis shouldn't depend on the size of the molecule, just the number of C and H atoms that need to be oxidized to carbon dioxid

The amount of oxidizer on a molar basis shouldn't depend on the size of the molecule, just the number of C and H atoms that need to be oxidized to carbon dioxide and water, respectively. Some molecules (ex. ethanol) also have some oxygen already in them which reduces oxidizer needed but also reduces the energy density of the fuel (its basically partially burned already).