Paul, What kind of pump do you use to get that much water volume to circulate the entire track.... thats alot of water that has to get pushed a long way... dont worry, there is NO under lying joke there anywhere.
Got a 3" trash pump in the pond right next to the table top. We are using 1-1/2" pipe. We have 3 zones and even running 2 zones together (one with a 243' 1-1/2" fire hose on the end), we get a good volume of water.
Being pretty much in the middle, non of the runs are that long.