If you want a long lasting FG/SS setup, go 1/8" track chain. 1/8" DuraAce or UA Imports cog and appropriate 1/8*" chainring. It will take you many thousands of miles to get 1/6" stretch in 12" of chain. (5000?) And if you can live with a little roughness, you are probably less than half way to replacement. $35 (cog) + $20 (chain) + $50 (ring) = $105 for a first class drivetrain and 10,000 miles.
There's a reason all kids bikes, 3 speeds, cruisers, etc. use 1/8" chain. For a low powered application to be used in an exposed environment where it will be treated badly, a basic engineering reference book will steer you to 1/8". The bike designers 120 years ago were some of the brightest minds on the planet. They got this one right.
Ben