Double insulated pipe

[softmaple]

What's the general consensus of using double insulated stainless steel pipe for the whole section of the chimney so the double insualted part would be attached directly to the evaporator hole and continue up through the roof as opposed to using the double insulated portion just for the section around the roof of the shed and converting to regular stove pipe that is connected to the evaporator? What is the best type of rain cap to use on the top of the chimney? Should I use one that looks like a chinese hat or one that flaps open and shut, taking into account that the pipe has insulation in it and could possibly get wet?
I have a 2x4 evaporator with a 5x10 inch chimney hole.
Thanks

[WESTVIRGINIAMAPLER]

For your smokestack, you should use the one that flaps open as you described it. You can open and close it from the ground every boil if desired and this way, it keeps the rain out. You don't want any restriction on the draft and the hats they put on the steam stack seems to me it would hinder the draft a lot. :?