Hi
Just to make sure that im reading this correctly your LO wakes at 6.30 and first nap is at 8, so that is 1.30 A time. From what you have posted your LO sleeps through the first sleep cycle so not a problem with transitioning here. Generally babies at 4 months have A time of 1.45-2 hours, try extending the first A time by 10 mins and hold for 2-3 days and see if that gets u a longer nap, if u get a longer nap then increase the second A time two. Let us know how you get on