If that were possible with the fuels rockets use (liquid hydrogen, liquid oxygen, liquid methane, etc.) it is still probably way cheaper on every axis to just m

If that were possible with the fuels rockets use (liquid hydrogen, liquid oxygen, liquid methane, etc.) it is still probably way cheaper on every axis to just make the tank 3% bigger and ignore the waste. Common axes they care about in rocket design are weight, cost in money, reliability/complexity, and lately reusability.