@forevercurious. At 4.5 months (after about 3 weeks of 1 to 2 hourly wakings) I started sleep training just at night.
I have found the opposite to you, that it was much easier to settle him in the evening without feeding than during the day. During the day he fights all his naps and will currently only nap on me in the sling. If you have any tips here that would be great 
When he wakes during the night at around 11pm and 3am I do feed him back to sleep but I think he is actually hungry then so I don't mind.
In the evenings I do feed him first and he gets quite sleepy. I then make a point of semi wakening him to change his nappy and put him in his sleeping bag before I put him down.