I have never weighed the apples that I juice. I use pure juice for my Apple Wine.....add sugar and the 'Usual Cast of Characters'.....[acid blend, tannin, nutrient, etc.]
I did weigh the Crabapples...Think I used 40# to get 10 Quarts of juice....To that 10qts. I add some Frozen Apple Concentrate too, that layers and adds to the flavors....as well add some water, sugar, etc....and the 'Usual Suspects'....[additives]
The steamed grape juice varies, I use almost pure juice in that wine too.
I have never juiced pears....Have bought a 'mate' for our old Pear tree and hope maybe this coming year we will get some little hardy pears. I have read that pears are not the most rewarding fruit to juice. I think some Forum members have juiced some and said they weren't too juicy, but the juice was good. Don't know if they added water or used pure juice.
I tend to use more fruit per batch when I steam juice my fruit.....just like a more flavorful wine....
Tho Chokecherry is one that I don't go over too much on the fruit/juice in that wine....it gets too strong.
Keep us Posted on your ventures.