The thing you've got to remember Shellbell is that whatever rhythm you decide on, you'll be doing approximately the same amount of pp/pv days in a month (as Dr D explains in the book), so if necessary you can decide on your own unique rhythm each week around what suits you and your circumstances (as long as you roughly end up with 50/50 pp/pv over the month).
For me Friday PV is an absolute must as it's fajita friday in our house... though admittedly mine are now somewhat lacking in tortillas and cheese lol!!