I recently bought a used practice set that was made by Charles Roberts. This is the first I have actually held a set of UP’s in my hands. I contacted Mr. Roberts by email to inquire about caring for my set and procuring some more reeds. I live at an altitude of 4700 feet with a humidity of 5- 20 % and a temperature range of -40 to +85 degrees F. Not exactly like the Emerald Isle. Mr. Roberts has been extremely gracious and helpful. I received three reeds today and was amazed at the giant leap that my playing ability took. I had to adjust the bridle on each reed 1mm to the tip. I think that is nothing short of magic considering the fact that he did that without my chanter and for a climate much different than his own. I think it says something about the construction of my chanter also. All three reeds play right on for 2 octaves. To say that I am ecstatic would be an understatement. Mr. Roberts has certainly earned a happy customer in a very short time. 
My understanding is that he has many happy customers. Good luck with your piping!
Dionys