I'm applying to grad school and have requested a professor to write a recommendation letter. He said he'd be happy to write one for me. I had worked on two projects with him. While working on the first one, I was a full-time collaborator and I was able to deliver the targets we had set out. This was two years ago.
During the beginning of this year, we decided to start working on another project. However, I couldn't devote much time to it because I was working on a full-time job. My responsibilities on my job kept me engaged and I couldn't make much progress. Slowly this project fell through the cracks. Since the professor is an extremely busy person it is unlikely that he would recall details around the first project. I'm worried he would unwittingly be influenced by the failure of the recent project.
How do I request him to take into account the fact that I was busy with a job while working on the second one and hence factor the first(successful) one strongly into the letter? I do not want to ask for it directly because it would appear pushy.