Both of my Taurus have the sagged wing skins, both use 3/32 skins, no dope and plastic covering. OK, I build light and select wood 'fit for task' but the point remains, this sagging is not unusual. With doped and silked surfaces it would be an expected result, and the older the airframe...As far as 1/16 wood is concerned, I use it for most of my wing skinning, 3/32 is pretty heavy stuff, compared, and my scale models tend to be a bit bigger, 90 to 120 " stuff, so I need to save weight where I can. You can limit the rippling thing by sanding skins before attaching them to the wing, if you pre-curve damp before gluing, then allow days to dry before attaching, and using non-shrink dope (Banana Oil) to seal and attach the covering if you are not using films. Banana oil does not sand well, so you have to use not much, and sand carefully before priming. As to what skinning Ed used, well I cannot tell, but given the weight of the finished Simla, it would have been light, so the rippling is not in any way strange.
Evan.