Three weeks ago got ground cultivated, irrigation installed, topsoil brought in, hydroseeded. Very glad got a firm to do it is as it took three guys all day for 100m2, with digger and various tools. Wasn't cheap but 3 weeks later we have a lawn-in-progress, and wouldn't have if I had tried to do it alone.
We went for MP Rotators as heads but a very simple 2 zone $80 Mitre10 controller, running off the tap. I'm looking at OpenSprinkler but can always add later. The shape of your section will have a big impact on how many heads you need, and that and the water pressure will impact how many zones you need. I've only heard good things about the MP Rotators and the tap controller was recommended as you can do e.g. 5 mins every 3 hours, which many digital ones can't. Are you considering going for tap connection or direct off mains. We went for tap due to small area and good pressure, but mains is recommended for larger areas and maximising pressure.
I agree 7m3 is not a lot of soil for your area; we had 7.5m3 for 100m2 area and could easily have done more.
Thanks. For your MP Rotator setup, do you recall what your flow rate (aka 9L bucket time test) was? I can run off a tap that comes into the house from the street so it's before the pressure regulator so theoretically should have plenty of flow but it's poor - about 23L/min so can only run a few sprinkers at a time.
Are you in Auckland? If so can you say who did your seeding?
I think we are about 23L/minute as well. We have 4 heads on one zone and 6 on another, but none of them have to do massive distances.
I'm not in Auckland and used a small local firm so can't advise on Auckland firms.