I apologize if this has been asked previously – I’m sure it has.   I’m remodeling a bath and am in the process of installing a 1700 series Delta shower faucet.   The instructions that come with it are not very detailed, to be polite.    I am installing through 1/2 inch sheetrock and 1/4 inch Swantone shower wall enclosure.   The directions state that if I install on a wall less than 1 inch thick I rotate the plasterguard 180 degrees.   This implies that I leave the plaster guard on the valve assembly and cut a rather large hole in my wall?   So I really do this, or is the plastic plaster guard only a reference as to where the shower surface should align flush to?  Thanks