There are some automatic waterers on craiglist - two are Miraco 2900 that are one year old and two are Hoskins. All are double. I wonder about what it takes to install the used ones and how one ensures they don't freeze?
Wood fencing is always a mystery to me. In Colorado (dry but strong UV) what kinds of wood is OK for a three or four rail wood fence?
Contact thye manufacturer and get proper installation instructions. Do not use green treated lumber as it has salt in it and horses will chew on it. Brown treated is the best for horses and 2x6 holds up much better than 1x6