The tops of the domes proved to be a tougher project than projected.  Closing them in and making a small cap of cement is no problem, as bags naturally close as one goes up.  But inserting the ventilation tubes at angles that will actually extract hot air required a second shot. We started with 90 degree 2 “ PVC piping, but forgot to insert plastic screens (bye bye bugs!) and decided, after install, that 45 degree elbow pipes will work much better and facilitate flow easier.