I've got a log shop 60x40 open with 15' ceiling insulated above and a metal roof. To use it as a workshop/winter I can get a good used BK princess which has a 14" box stack and a 6" class A chimney inside..so i'm told. My studs are, i think, 24" apart above. Is the easier/better and/or safer way to go straight up through the roof or do a 90 degree out through the log wall? any thoughts/considerations one way or the other? thanks.