The rice tea is already in cups, so I know that's not a problem..
I don't think there will be a straightforward conversion formula from weight to volume (Different substances have varying densities, and would therefore have different weights for the same volume), but I deal with ounces and herbs and vegetation every day and here is what I would do in the absence of a measuring scale:
16 ounces white daikon
8 to 10 ounces white daikon greens
8 to 10 ounces carrot
8 ounces burdock root
3 to 5 fresh Shitake mushrooms sun-dried. If not sun-dried, expose dried mushrooms to sun again.
Don’t Peel Anything
Those roots are probably all pretty much similar density/weight, so I'd go by proportion, i.e.:
1 part White Daikon
A little over half that (Weight of the White Daikon) of Carrot
Match the weight of Daikon greens evenly to the same weight of the carrots
(Using any kind of homemade fulcrum/balance/seesaw setup)
Half (Weight of the White Daikon) of Burdock Root
(You could use the same fulcrum setup as with the greens to match the weight of the White Daikon with Burdock, then eyeball the Burdock and cut the amount in half.)
3 to 5 Shiitakes is easy to figure out..
That's what I'd do if I didn't have a scale.
My guess is it's not that important to be totally precise, IMO any ballpark should get you close enough.
Hope this helps.. Please post when you make it :). Thanks.