Aside: I really want to encourage you to do this. In my previous job, I went to 40% time so I could spend 60% on my startup. This let me make enough money to get by, while freeing up a huge amount of time. This was incredibly valuable, and the experience of working part-time like that will be something I will definitely consider in the future when personal circumstances (like children) make it desirable, and I think I was contributing more than 40% of my previous full-time value.