How do i set my handling time for ALL orders

[Hoddahsmash]

I want to change my handling times from the default to 6 whole days due to changes in my day job. I want to have insurance against missing the shipping deadline if I end up having to stay in a hotel away from home. I have over 200 listings and the only way I have found so far is to individually go to each listing and enter 6 into the handling time field. Is there a faster way of doing this?