You might ask at biodieselnow.com for clarification, however biodiesel has no such issues you cite as issues with WVO. Biodiesel is chemically converted from vegetable oil, and has no viscosity or polymerizing issues that WVO has.
The problems you cite with coking that are associated with burning vegetable oil were found on older direct injection engines burning cold oil. The Mercedes engines like the 617 are indirect injection and will not get any unburned fuel into the cylinder where it can coke. As long as the oil is properly heated before burning it, you should have zero issues in a Benz.
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