The conversion from mole composition to mass uses the molar mass. One mole of a the core ester group R'-COO-R has two O and one C in moles. Expand the atomic composition in C, H, and O for the R' and R groups the same way using a basis of one mole of your compound. I have done such calculations directly in a spreadsheet application.

Fatty acid containing S is excluded in this answer but you can added in your calculation if the exact composition ids known.

The general chemical formula for a fatty acid methyl ester and their mixture is;

CzH (2z-1-2Nd) OOCH3; where z, number of carbon atoms of fatty acid; Nd, number of double bond(s).

For methyl palmitate, C16H(2×16-1-(2×0)OOCH3 or C16H31OOCH3 and the nominal MW = 16×12 + 31×1 + 47 = 270.

For methyl oleate, C18H(2×18-1-(2×1)OOCH3 or C18H33OOCH3, MW = 296.

For methyl linolenate, C18H(2×18-1-(2×3)OOCH3 or C18H29OOCH3, MW = 292

Similarly, the general structure for the mixture of FAME is CzH (2z-1-2Nd) OOCH3, where z and Nd are the average number of carbon atoms of fatty acid and average number of double bond(s), respectively.

The average of both values can be calculated from fatty acid composition according to (J Am Oil Chem Soc (2016) 93:1407–1414. DOI 10.1007/s11746-016-2874-x),

 (This mathematical formula cannot be shown, the file contained the formula is attached

Thus, H/C, O/C can be easily calculated from the chemical structure.

Dear Colleagues,

I am impressed by  your explanation but still have some issue. Highlighted in Table 1 is the values of the fatty acid composition of biodiesel determined from GC.of the B100.

How can determine the mass fraction  values of h/c, o/c and s/c for B0, B7.5, B15, B22.5, B30, B37.5, B45, B60 and B100 in order to determine Ef for the  B0, B7.5, B15, B22.5, B30, B37.5, B45, B60 and B100, please.

Table 1: Acid Methyl Ester Composition Based on Percent Mass biodiesel

Caprylic  (C8:0)-       0.485

Capric (C10:0)-        0.388

Lauric (C12:0)-          1.133

Myristic (C14:0)-       1.432

Palmitic (C16:0)-     32.792

Palmitoleic (C16:1)-  0.111

Margaric  (C17:0)-    0.174

Stearic (C18:0)-        4.381

Oleic (C18:1)-          43.000

Linoleic (10:2)-        12.660

Linolenic  (C18:3)-    0.942

Arachidic (C20:0)-    0.567

Arachidonic (C20:4)-  0.779

Behenic (C22:0)-   0.418

Erucic (C22:1)-    0.208

Lignoceric (C24:0)- 0.525

Dear Colleagues,

A good paper entitled, "Shahavi, M. H., Hosseini, M., Jahanshahi, M., Meyer, R. L., & Darzi, G. N. (2016). Clove oil nanoemulsion as an effective antibacterial agent: Taguchi optimization method. Desalination and Water Treatment, 57(39), 18379-18390",   you can be explored  for Taguchi study.

there are other than ester components in a "FAME" product, these are rarely checked in routine analysis