I get a little wordy for facebook so I'm going to respond to a post there with a link to here. I saw a thread that is providing a newbie some guidance that is contrary to my experience. Here's my opinion:
Silver stain works better on the tin side of float glass than on the non-tin side. Silver stain works better on the tin side of float glass than on most glass, in fact. You can see tests confirming this in Ken Leap's book on silver stain. There is no dullness or lack of transparency in the result. However since the stain does react more strongly on the tin side, the result may be stronger than expected. I wouldn't call it dull and brown at all. The transparent enamels from Reusche and other vendors work fine on the tin side of float glass. I know this from experience. But I didn't know about the test for float glass by observing a water droplet. So I went down to the studio just now to try it. I couldn't see any difference in the surface tension of a droplet on either side of my meticulously clean test strip of float glass. I used distilled water, so there may be more value in using tap water. I use a hand-held UV lamp made for purifying surfaces for determining the tin side of float glass. Mine's from 'Purely Products' and didn't cost much.