I too would suggest that you re-think the sidewalk. It's not very difficult to get a single pipe under a typical 3' wide sidewalk. I live on rocky clay as was able to get a 1" copper main under an 11' wide driveway, 5 latteral lines under a 5' wide section of sidewalk, and 3 latteral lines under a pair of 3' side walks. If I can accomplish all that in clay, then surely you can get one single pipe under a side walk.
There are tons of ideas out there for getting under a sidewalk if you have soft loamy soil.
Here's a few ideas if you have hard, rocky, clay soils:
Dig your trench leading to the sidewalk. Get a 4' piece of rebar and "drill" a pilot hole under the sidewalk by beating the rebar with a hammer. Increase the size of your pilot hole with a strait nozzle attatched to a garden hose. Other alternatives to increasing the size of the pilot hole is to use a pressure washer (gas or electric) if one is handy. If not, get a 4' piece of black pipe. Place a reducing coupler capped with a nipple on the end of the black pipe (to form a crude arrow tip) and hammer the pipe through the pilot hole. From a size perspective, I can tell you that a 3/4" black pipe tipped with a 3/4" - 1/2" reducer bushing will form a hole the perfect size to slide a 1" piece of PVC through.
To maintain matched precipitation rates (MPR), best not to mix MPR 10's 20's and or 30's on the same zone. The MPR denotes matched within a certain coverage, so all MPR 10's are matched, as are all MPR 20's but not a combination of 10s and 20's
Based on the documentation at
www.mprotator.com, I've got to respectfully disagree. This is one of MP Rotator's selling points, that all of thier products have matched precipitation rates so that you CAN mix them on the same circuit. Assuming square spacing, here's the precipitation rate ranges for the different products:
MP1000 0.37" to 0.43" per hour.
MP2000 0.35" to 0.44" per hour.
MP3000 0.37" to 0.44" per hour.
MPStrip 0.48" to 0.49" per hour.
Given that irrigation isn't an exact math, I'd call that pretty well matched.