Vp I do SOS and with 3 boys that morning sleep just has to happen in the pram or car.
I think for us ds3 will work better on a 630-630 routine rather than 7-7... Just gives me half an hour to BF before the other 2 wake up. Then 830 we're in the car and on our way to school. It also means if I've got to go shops etc I can be home in time for ds2 to have his nap.
Today I've done 7-7 and I'm still walking around the shops waiting for ds2 to wake up and then go straight to school pick up for ds1.