There is a definite relationship between the Inert mass and the Propellant mass in a stage, exclusive of the Payload Mass, called Propellant Mass Fraction, Lp, which can be used to determine whether the guess for GLOW is good or bad.
Lp = Wp / (Wp +Wi)
Values of Wi, Wp generated for a
given GLOW can be checked
against a pre-assigned Lp.
Realistic Lp values are: 0.7 to 0.9
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