I had a look at the GF thing (my little boy is 10 weeks now) but never tried to use it as I personally felt it would be much too rigid for us both.
I think like a lot of things it will work for some babies/families but not others.
So, I muddled through the first 6-8 weeks following his cues cos I'm a FTM and didn't have a clue
From 8 weeks he started to fall into his own rough schedule and we introduced a loose bedtime routine of bath, milk and then bed.
At first he would go to bed around 8pm but now he's brought it forward himself to 6.30pm (we obviously bore him in the evening lol).
So now, our days look something like this depending on what we have on.
Ds wakes around 6am when dh gets up for work but happily gurgles next to me in his crib while dh showers etc. Then dh takes him down around 6.45am while I shower.
From 6.45am to around 7.45am ds is in his bouncer or moses basket usually smiling and gurgling while looking at the lights! We chat to him while having breakfast and watching the morning news 
7.45am - I wash and dress ds
8am I feed him and he drinks about 7/8oz.
Then we have cuddles/stories/short play and he tends to have a sleep from about 8.45am-9.30am.
Then if it's a day when we have a morning activity (thur/fri) we go to that. If we have an afternoon activity (mon/wed) we play at home.
He has a feed around 11.30am/ 12pm - again 7/8oz then sleeps for about an hour before we either play or go out depending on the day.
He has another feed around 3/3.30pm and takes about 6oz. Then I usually put him in his bouncer and take him with me while I prepare dinner/do a job. Sometimes he has a short snooze, sometimes not.
Bath around 5pm and then he usually has another 6oz of milk around 5.30pm/6pm.
Then into sleeping bag, cuddles and in bed at 6.30pm.
He generally wakes once at around 3.30am/4am and has 4/5oz before going back to sleep.
So he has 30-33oz of milk in 24 hours (he's a big baby) and I think for 10 weeks he sleeps really well.
We tend to go to be around 10pm so I get a good 5/6 hour block and then another couple of hours which is good for me.
If we have to go somewhere at a particular time e.g. doctors app. I just alter things a bit and he is happy to sleep in the car/pram.
So he has a routine which is probably not hugely different to GF but is led by him and we can change it if we need to. He's a happy, thriving little boy so I guess I do something right somewhere!
Have a go with GF as it might suit/work for you and your baby but honestly don't stress if it doesn't. I thought at one stage (around 5/6 weeks) that we'd never have an idea of what would happen when but they quite often do find their own pattern eventually.
Clearly if their pattern includes being nocturnal then I can see why you would want a stricter daytime routine!!
Best of luck xx