It sounds crazy to use a source of a non-anamorphic DVD sourced from a piece of shit master from the early nineties and end up with a 25GB file.
Even though I have no hardware capable of playing such media back, I'd be sorely interested in a short video explanation of your process. Perhaps dissect a shot or two and show us what all went in to it.
For the time being, until my home technology advances, your V3 DVDs are my archival "Star Wars Trilogy." And they ain't half bad.