I see, I will take a gamble and buy it... rated at ~500mAh with coil and charger directly aligned.
With my Otterbox Commuter case, I think the charging should not be affected too much (my guess is around 480mAh-490mAh)
This is because the Touchstone, like the Qi, is using EMR for coil and charger transmission/receiving. The only different is that Qi and Touchstone operate at different frequencies and the coil designs might be slightly different to have either slightly better range or better efficiency.
From my experience with Wacom tablets (Intuos, Bamboo) and Wacom integrated tablets (Galaxy Note 10.1, Note 1/2, Tablet PCs, Cintiqs etc)
The pen can hover even with an overlay sheet or a pane of glass over it.. The hovering range is around 5-7mm depending on how thick the surface cover is.
Hopefully the charger has a built in tinkle charging mode and a auto shut off mode (the phone power management should have this)
Also hopefully it does not overheat the phone when it is charging through my Otterbox Commuter case.