Opted to install "thick wall" cylinders rather than reuse the originals from Revmaster. These are often sold for VW buses to "increase cooling" due to the thicker wall. Thermodynamics will tell you, however, that once any material has reached steady-state the thickness does nothing to improve cooling. In fact, the thicker wall reduces the height of the cooling fins compared to a stock cylinder. What the thicker wall will do is to help prevent the cylinder from going oval as it keeps up under continuous load. This particular phenomenon is mentioned in the VW red book, although I have not seen it brought up anywhere in the aero-VW world.