a. Feeder should be placed 10 feet away from any trees, overhanging branches, roofs, etc... anything that a squirrel could use to jump down onto the feeder. As you can see from the photo, one of my feeders is fairly close to the tree line ( ~10ft ) so it shouldn't be impossible to find a good spot for this feeder in your own yard.
b. Feeder should be 5ft off the ground, though the first feeder I setup was around 4 1/2 feet. The pole used in this instructable is 6ft tall so you should be good to go. You simply want to ensure that the squirrel will not be able to jump from the ground to the tray directly. The lower baffle has a large enough diameter that the squirrel will not be able to climb it.
How this squirrel proof feeder works:
Since the feeder should be placed 10ft away from trees, roofs and overhanging branches, and has it's tray roughly 5ft off the ground, squirrels should only have one route to get to the feeder's tray; up the pole. The baffle under the tray will be 2 feet tall and have a diameter of 6 inches. I have found ( through trial and research ) that a squirrel cannot climb up a pipe of this size diameter. Also the baffle is open at the bottom allowing squirrels to climb up into the baffle into a dark chamber where they are confused as to where to go and inevitably return back down the pole.
I cannot guarantee 100% that this squirrel feeder will work for you, however prior to using these types of feeders my yard was infested with squirrels. Now that I am using these style feeders I at most see 2-3 squirrels in the yard at a time, and have noticed that unlike other setups I have tried they lose interest in trying to get to the seed rather quickly.
I have created a video to go along with this instructable that can be found at the below url:
Part 1: http://www.youtube.com/watch?v=3Qdm747cols
Part 2: http://www.youtube.com/watch?v=xxdxdck4Syo