Put a T on top and place a 1/4" SS hardware cloth over each open end. Try to face it in the direction of the most common prevailing wind. Attach them with a Band clamp to hold it in place. I also suggest you add 1' more, the formula for chimney height is to be 3' above the exit and 2' above the highest point within 10'. If your stack is real close to the cupola, 3' is safer.
Dave Klish, I recently bought a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.