Looking for some advice ...

Need to design and install a residential irrigation system. The water source will be via a tank and pump, beings that the "well system" (2 party) is inadequate to supply any kind of irrigation system. I know itÂs recommended that you first calculate your available water supply in order to design the irr. System. So, am I better off selecting a pump and then designing the zones or design the zones and selecting a pump to match? For optimum pump performance, it should not cycle on and off, it should run constant during each zone. (correct?) So, if I design each zone to require the same GPM, I should be able to select a pump that would function correctly for this system ... yes/no?

And ...

If a pump has an outlet size of say 1" ... is there any benefit to running a main supply line larger than 1", say 1 ¼" ( to decrease friction loss due to long distance or grade/head)? I know there are calcs to figure out friction loss in main supply lines and laterals, but is there a "rule of thumb" that typically applies? Do you calc. lateral pipe size per system or run a particular size pipe for all jobs?

And.... (one more)

Any good sources for info online pertaining to the above?

Thanks.