Best work schedule with an infant

I have a four month old and am going back to work in two weeks. I originally planned on working three ten hour shifts ( 7-5) with a twenty minute commute in the morning and thirty minute at night. However, I am now wondering if it would be better if I worked four eight hour shifts instead? I could have an 8-4 instead.

I am still pumping six times a day and will also need to hire a nanny - it would be two ten hour shifts vs three eight hour shifts (husband has a weekday at home).

I can see pros and cons either way. Does anyone have experience with this and advice?