Well, this is how I have been doing it:
Mon: Right cheek
Tue: Left cheek
Wed: Left delt
Thur: Right cheek
Fri: Left cheek
Sat or Sun: Right delt.
So I am really doing 6 days/week, and with my 25g pins I seem to be doing ok. This way, I hit each spot twice/weekly. I would prefer once/week, but you do what you can.
It makes me wonder how E2 does what he does. Damn.