I have absolutely no idea.
I need 16 cups (liquid measure) of tomatoes to make a double batch of V-8 Juice. If I’m bothering to make ONE batch, I’m making TWO!
All of my recipes call for ‘cups’ of this or that. No actual ‘weight’ of things, other than for making pickles...which always ask for measures in ‘weight.’
Why recipes between various foodstuffs vary so much? I do not know.
I loved the way we made V8. We have a champion juicer, a wedding gift from 1978. A real workhorse. Best juicer ever. It DOES get heavier every year. We did our V8 by volume and taste testing. Started with the tomato juice, When we had enough we added the other juices, carrot, celery, onion, cabbage, pepper, whatever else. We did not cook it at all. We added spices salt and pepper, etc. last and when it was right we canned it.