Well I did it: Climbed up there, putty in hand, and filled those holes in my wall. Does it look good? No. Is it good enough? Yes. I'm very pleased with it. Only a person who really stood there and looked at the wall would notice the lumpy mess I made. I'll get better, but mostly I'm just happy for the satisfaction of knowing I could do it. Thanks to all for the great tips and support in doing my first project.