I am reseaching Rust also, my family were all from Aberdeen and the name George is popular among them as is William. I went onto the Scotlandspeople website and checked out Ethel Rust, as you can find births up until 1905, but there were no Ethel Rusts, not even in the 1901 census. Are you certain about her name? Could she have been christened Jane? I also looked for a marriage for George Rust and **** Mckisson but nothing there either, I checked out the name Mckisson also, and there were very few in Scotland, even with the spelling McKesson. Are you certain the family were Scottish?