Have you considered purchasing one of these piping kits? These fit Drolet, Century, Englander, Buck Stove, Enerzone, Osburn, and any stoves with a 6" flue diameter.
Reduced clearances up to 5"!
This kit contains: 1x appliance connector, 1x telescoping section 38" to 70" and 36x self-tapping screws.
These piping kits and piping are made from 24-gauge steel