Hi. Am adding an outdoor shower on the side of my house and could use some advice. I know it is not ideal, but I am working on connecting it to a hot and cold 3/8 in copper valve that previously supplied a sink (trying to use as many existing connections as possible). Would be using PEX tubing that would run about 25 ft. Coming from a 3/8 in copper pipe, would the size of my PEX tube make much of a difference downstream? (i.e. Would 3/4 in versus 1/2 in PEX be better for flow and pressure or will it even matter with the 3/8 in supply pipe it's coming from?) Many thanks!