Hi, new to this site and it looks like you are the people I need to talk with! I have a galvinzed water system 60+ years old. I was thinking of replacing it with cpvc because the flow is almost down to nothing. I have 1/2 inch rizers going to the second floor. Could I use a 3/4 inch rizer to the shower to increase volume? We like a thunderstorm in the shower. Any reason not to use cpvc? I can sweat copper if it is a better choice. Thanks in advance, Gordon