Since some seem bored with the 7 head battle I thought I would throw a theory out their and inflame the manifold folks. My point on the 7 head post is that manifold people and pipe pullers design their systems in which the heads are in a long series and downplay the psi difference between the first head in the series and the last. I was taught to find the midpoint and split the zone to minimize pressure differences between heads. Since installation methods (pulling vs trenching) (coming from the house vs street) and labor are such a big factor in irrigation installation we rationalize to justify what it takes to install a system profitably. This is not the point to this thread though. I think the tradition of TX irrigators installing single valves in the yard started in the days of copper systems. The cost of copper and labor involved sweating pipe mandated that systems be designed to minimize the larger copper sizes and allow for pipe downsizing as soon as possible. Combine this with our tie-ins always being at the curb. I'd like some manifold person to take an old design and redesign it using the TX method and do a material take off.