Livonia Solidus, Schilling, Silins KM# 21 - Weight?

I think "the size of a US dime" is an overestimate (I didn't measure any of my examples, but a brief search seems to say 15-16 mm, which is actually half-dime size). They're pretty darned thin though!
As for weight, a brief check of sales where the weight is listed gives a range of 0.46 to 0.59 grams (I probably missed a few values slightly higher or slightly lower); no idea what it's supposed to be "normally", but probably roughly in this range (i.e. something like 0.5-0.6 grams).
I have no idea about the silver content, unfortunately; from what I could find (I've tried to research this question several times earlier), it probably varied a lot, but certainly wasn't much (I recall some mainly-unrelated article that estimated 10%). There's an example at FORVM listed as "silvered billon", which is probably as good a guess as any.