G'day Benjamin,

Not necessarily, it depends on your set up.  If it does need support, you just use an awing pole with a spigot - there's a small tube for this factored into one of the chimney pieces which you can see in the product image.

G'day Alex,

The Ozpig comes with 3 chimney pieces, so getting the 2 piece offset kit gives you a total of 5 lengths.
I'd say that would be enough for your setup, but the 4 piece is pretty good value for an extra 2 pieces and it may not hurt to have some spares.
Either way I think you'd be ok - might also be worth jumping on the Ozpig facebook group and seeing if anyone else uses their Ozpig under a gazebo & can show you their chimney set up.

G'day Troy,

I've just double checked this for you and unfortunately not, the big pig has a chimney with a much larger diameter.

G'day Tim,

I've just measured the Ozpig Chimney, and it is approx 60mm in diameter. They have a sleeve section in order to stack the chimneypieces, so this may vary by a few millimetres depending on whether it is the top or the bottom.