PRS tops are much thicker than 1/2"
I would say about 3/4" (19mm) at the highest point. For a deep carving like a PRS you need about 1/2" (13mm) for the carving itself (I used 13mm for my build), and add something between 3/16" to 1/4" (5 to 6mm) for a faux binding to make sense.
For my next build (carved top, faux binding) I got a 19mm top.
0.69" (17.5mm) is doable, but probably too close a call.
Now 1" is more than enough, but maybe too much: you'll want to concentrate your efforts in the carving, not into converting 5mm of maple into sawdust to get it where you need it. Believe me, it's a lot of work. Maybe you can ask the supplier to thickness it down to 3/4" before shipping ?? I know the german provider I bought from will do that upon request.
actually my friend has a PRS Private stock #805. and it only has a 1/2" top the SE's have a 1/4" inch top (if i remember right when i measured at guitar center)