Plumbing water heater with manifold system
On manifold systems, I have never seen the hot water taken after the cold manifold. It has always been a tee off the main line. If you are running dedicated lines to each fixture in all locations, 1/2" lines will work in all cases. If you are going to branch off to other fixtures using one line to do multiple fixtures, say one line to do a bath, another to do the kitchen and another to do a hall bath, you need to start with 3/4" lines from the manifold, then reduce to 1/2" after a few fixtures have been fed.