Hi Brian,
Congratulations on starting on the pipes. When asked about how difficult it is to play the pipes I generally explain to folks that the chanter only has 9 notes, so it's fairly easy to get started on, but it takes a very long time to master.
I'll offer a different opinion on the practice chanters. I've found a standard length to be more comfortable. You generally play the PC while seated at a table, with the end resting on the table top. The long chanter might be a bit awkward. The finger holes of the longer chanter are spaced more like those on the actual pipe chanter, but regardless of which length chanter you choose, your hand and arm positions are very different when playing the practice chanter as opposed to the pipes. What I have found to be more important than the length of the chanter is having finger holes that are countersunk. This makes it easier to position your fingers, and gives an approximation of the feel of the larger holes on the actual pipe chanter.
Again, congratulations, and I hope you enjoy yourself.