Hello,
I was looking for something similar a few days ago. I found this thread that speaks of a tool called wishful mockup. Although I have yet to seek it. I did however find some valuable information on the thread. Hope it is helpful.
Personally I take the cubic milimeters and translate to cm3, and then multiply by specific gravitates of the metal I plan to work in. A button would be useful surely, and especially if it was connected to the current spot price of precious metals.
Hope this is useful.