Thanks so much for the reply......a little more info.
The chimney that I'm going to install the stove in has plenty of space on its sides at least 10 inches per side....I feel pretty good with that since I am redoing all of the chimney brick and refractory cement on it. Also I don't think I'm going to light it up like the fourth of July...planning to be a little conservative burning it really hot. If single wall pipe is okay to use for a 25 foot run with plenty of clearance around the pipe that would be more cost effective for me. My concern is with it being such a long run will I have problems with the draft and creosote build up? I do have a rather large addic and does get cold in there during winter days.
As far as the top of the chimney it does go past the peak of the roof 5 feet and don't see a problem with the pipe going through the top of it, as the chimney box is covered with only a sheet metal top.