If you are going with a pump I highly recommend using 3/16. I have found that you do not need to be as concerned with slope as you do with 5/16. I have 95 taps on one pump and 150 on the other in the same woods with some 3/4" main and now all 3/16 lats. I have some 3/16 lines with about 20 taps on level areas and only lose 1 to 2 psi at the end. I just run the 3/16 from tree to tree and it goes up and down appr. 3 feet through the run. I have three 12 volt 2088 shurflo pumps with 3 years of use and have not had any problems so far with them. During runs last year I was getting 24 to 25 inches of vacuum with them. On one of my better runs last year I got 2.3 gallons of sap on the pumps and 1 gallon per tap on the bags in that same woods.