RainBird shows 40' with a 3.0 nozzle in the 5000 at 45 PSI (http://www.rainbird.com/documents/turf/chart_5000.pdf
). If you use 3.0 on the corners and 6.0 for the 1/2 circles, you could do it with 6 rotors. You'll need to split it into 2 zones though, 12GPM is about all I design for through a 5/8 meter, you can push it to 15 - 16 but it's better not to.
Adjusting the distance on a 5000 is as simple as screwing the nozzle set screw in further. There's a limit to this, you don't want to dial it down more than about 20% - 25% or you're going to really mess up your pattern but it'll work for your needs.
It just so happens that the PRS version of the 5000 is set for 45PSI so that would be the ideal head for your design.