Very helpful responses, plenty for me to work with. In hindsight, I could have left out the "appropriate?" part of the question, and left it to the degree of bend in the arm. Went out late yesterday and shot just a little ( my fingers are getting cold fast this time of year!), keeping in mind McDave's suggestion about shoulder alignment, and, as always, Arne's points got me thinking... found focusing on my bow hand (wrist, actually) was probably part of my problem at fuller extension. That imagery of his about supporting weight on bones, rather than muscles, also helps a lot.
Wish I could find a mentor, or simply shooting buddies around here, but no luck so far, and as always, the TG family is where I look for help, and always find it.