Sue: Have you found the proof of service for L. G. Howes that you are seeking? If not you can write to the National Archives and request copies of the papers they can release. Their web site has the correct form to use as a downloadable .pdf file. Their URL is:
You know from the 1910 census record that he was aboard USS Gedney on census day and that he was aboard USS Orion on census day in 1920. Also you know from the census record for 1920 that he was a LT.Commander and probably the commanding officer of Orion because he is the senior officer listed in the census.