Build the ring into the cowl. Simple with the part Mike supplies, ring is cheap at about $15, and the mount is LOT cheaper, and the whole setup is lighter. I don't find the ARIA mount works as well as a separate ring with the 1.60FX in airplanes that are otherwise absolutely identical. A lot less vibration. Also, buy the Hyde mount with plastic rails. Cheaper, and they support the engine on both lugs, not just one.

One warning, don't cut out the cheek cowl cooling holes until after the ring mount is in. Mine was ok, but it was CLOSE.

Andy Pollitt sells the rings. http://www.countryworkshop.ca/planes/andy/home.htm

Jon