Products by Pennyweight

We sell metals to our jewelry students by pennyweight. For example, a student may by 2.8 dwt of rectangular silver, then 0.5 dwt of half-round silver. I can't seem to find any way to sell products by fractional weights in Selling > Products. Am I missing something?

There are a couple of ways that I have found. One is from Paul 2009:

Product quantities can only be an integer (whole number). I don't expect fractional units to be added any time soon.

The only workaround is to add variants with descriptions like "500g", "1 Kg", "1.5 Kg" and so on.

The other is if you use Square billing:

https://squareup.com/help/us/en/article/6694-sell-items-by-weight

Yeah, I read that, too. But that's bizarre for the end-user.  They'd have to add 28 units of a 0.1dwt variant to get 2.8dwt. That's a pretty lame workaround.