[Edit: Disclaimer - Some of what is stated below was from the point of view of the "typical" setup and NOT the specifics listed at the start of the post. As an example, an RPZ backflow is discussed, but the OP stated that ASVF valves would be used... obviously both are not needed]
Check your planned GPM flow rate and pipe sizes before you tie in after the house pressure regulator. If your house is set up like mine, you've only got a 3/4" copper line where the water line enters the house. That would limit your safe flow rate to aroud 5-6 gpm. Many residential sprinker instilations want higher flow rates than that (to avoid having tons of circits). To allow for flow rates in the rang of 12-14 gpm, you want to tie a 1" line right after the meter (unless they already have a 1" main running to a more appropriate spot to tie into.
Since having enough pressure isn't an issue for you, I would think you would opt for fewwer circuits and want flow rates in double digits.
The other negative to to making the connection AFTER your house regulator is that pressure then could become a problem for you (depending upon how your system will be set up). As an example, if your house regulator is set to the standard 50 psi and you're required to install an RPZ back-flow preventer, that means by the time the water gets to and through the valves, the pressure in your lateral lines leading to the spray heads will only be about 35-40psi (not including friction losses).
So while your particular situation may call for something different, I would think the best set up is likly to be for you to tie into the main just after the meter with 1" pipe, take that to your back-flow device and then a pressure regulator (the Watts 009 RPZ is designed for pressures up to 175psi) and then the pressure regulator. And if you buy a regulator that can be adjusted (more than the $10 models I pointed out before), you'll have the flexability of having as much (or as little) pressure starting at the control valves as you want because you could adjust the pressure of the irrigation system independant from the house (i.e. leave the house as the standard 50psi, and set the irrigation system to 70psi).
And yet another reason I just though of as to why you might not want to tie into your water main after the house pressure regulator... all the water for house use and irrigation use would flow through pipes up through the pressure regulator. So if you do have that 3/4" copper pipe, your 5-6gpm flow capacity would be for the combination of both house AND irrigation. So unless you only plan on running the system as say 3 o'clock in the morning, you'd need to design your irrigation system to stay under 5gpm.