I find that a tablespoon for silver needle or white monkey works fine for a 6-8 oz. glass -- and that gives me 2 steepings.
That said, I've ordered a digital scale to play with the accuracy. If
That said -- if you go that route, I'd recommend an accuracy of no less than .1 of a gram, with .05 preferable.
P.S. - The scale arrived. 3-3.5 grams of silver need for a 6-8 oz. glass works for me.