Hi All
A while back I said I would be trying this out... and I did... several times!
So, to start with, I bought a couple of "pre-fab'ed) (how's that for a pun) SG3 backs with the Palm charging coils & contacts in place. I got 1 on eBay, and one on Amazon. About $28 each. They were different in manufacture & layout - on one, the coil & metal disks were centered on the back (for landscape use, mostly), and on the other the placement was biased toward the lower half (so the GS3 could sit in Portrait mode without bottoming out against the tabletop/car console / whatever the Touchstone is on.
I tried this set-up au-naturel, and it seemed to work quite well - although the GS3 did not "stick" to the touchstone very well.
Not unexpectedly, when I tried with the OB case on (just the hard shell), it did not stick at all, and the wireless charging announcement would repeat itself endlessly.
So I ordered a couple of thinner cases (Ringke and XGear). Charging was OK, but still not "sticking" at all.
So I ordered some of the magnets on the link below:
K&J Magnetics - Products
And "Hey Presto" - a charging, sticking SG3 on my Touchstone. The Xgear case would work the best if it did not have the Aluminum backplate. I took it off, and it works, but there is a lot of adhesive gunge to remove.
The Rearth Ringke case works fine.
For those interested, I have also fitted the phone with the (discontinued?) Spigen Glas tempered glass scren protector. Fits & works like a gem. While I was using the OB defender, I was not aware just how much responsiveness I was losing! The Spigen Glas is great in that respect (though there is a little "adhesion bubble" (? don't know what else to call it!) right in the center of the screen.
All-in-all, I am thrilled with my Touchstone-enabled, glass-screen-protected GS3!
Cheers
russ