"I'm planning to go to Sardinia in August and I was wondering if anyone has suggestions for DWS locations (up to 7a)?"
The place we always suggest to guests is 30 mins down the coast from where we live
http://27crags.com/crags/cala-luas Has the advantage that no boat needed. See
The Golfo di Orosei has loads of things to do but not really documented and only accessible by boat. Mauro Calibani likes the Scala di Ferro near Cala Biriola, further south just as good I think is Cala Magroni see eg
http://www.peteranne.it/wp-content/flagallery/dws-deep-water-solo-golfo-di-...
http://www.peteranne.it/wp-content/flagallery/dws-deep-water-solo-golfo-di-...
On the west coast there is an arch near Oristano and the Pareti magazine (Italy's main climbing magazine) had an article about Capo Caccia, but this again needs a boat.
"Haven't looked into the sport climbing guide "Pietra di Luna", does it contain a chapter about DWS?" No it doesn't.
Honestly the sports climbing in Sardinia is much better than the DWS, and there is plenty to do in August, plenty of high-up shady crags: Ulassai, Jerzu Su Telargiu Oro, Serra Oseli, Genna Croce
cheers Peter