How much is 2 pounds of potatoes or whatever - do you use a scale?

[progree]

16. What triggered this today is a multicooker recipe for mashed potatoes

https://www.spendwithpennies.com/instant-pot-mashed-potatoes/

They were obsessing with how much water should be used in a multicooker for 5 pounds of potatoes -- enough for pressure cooking but not so much that the potatoes are soggy. Also the 1" of water is a lot more than the maximum 1.5 cups that is also stated -- in my 6 quart multicooker, 1" is 26.6 fluid ounces which is 3.3 cups. Quite a discrepancy.

Also, it's a recipe for 5 pounds, but I don't want to make 5 pounds of mashed potatoes at a time. And I want to follow the recipe, like do 2.5 pounds of potatoes and cut everything else in the recipe in half.

And then my multicooker manual says always use at least 1.5 cups of water for pressure cooking. If I'm cutting the recipe in half ... I can't cut the water in half to 3/4 cup.

I've been cooking potatoes in several different ways for 60 years, I'm not a ring-a-ding-dong. I just want to follow this recipe rather than winging it. I have no idea what 2.5 pounds of my very large Russett potatoes looks like, I'll probably just use 2 of them. (EDIT: potatoes have close to the same density as water, so 2.5 pounds volume will be about the same as 2.5 pints).

Some have commented that I can just weigh the right amount at the store. I'm sick and home-bound, so I can't go to the store and do that. I'm using a shopping service like Instacart called ShipT. I suppose I could make a special request for 2.5 pounds of potatoes, but I don't like making special requests.