If the rain sensor doesnt use the sensor terminals you have to make sure that there is a jumper from 1 terminal to the other.
I stand to be corrected...the toro with the regulator is the prx, not the 570z.
I would suggest using the hunter svc. Its a 9v timer that you attach directly to the valves solenoid. The only difference is that you have to purchase hunter 9v latching solenoids. Its very easy and a really good product.
Be careful with this elevation change. By the time you get to the top of the hundred feet you will lose 44psi. The formula is .44psi/Ft of elevation change. We have incountered this problem before and you either install the rpz, 2 backflows or a non dumping backflow(not code in new england!).
The 570z is different. The 570z has a factory installed flow shut off device. If for instance the nozzle gets broken off and the flow changes the head will shut itself off. It all sounds good but but I have had a lot of problems with these heads. Save yourself a headache and just get a regular 570. You should be able to get them just about anywhere.
The I-20's have a stiffer spring than the regular PGP's. I have come across this problem a lot especially on well systems. If even a little sand gets in the I-20 will not pop. Switch your heads to PGP's and you should be fine.