Will switching to BTC help with consolidating a nap?

My little guy is 6.5 months, and he's been on 2 naps since 5.5 months! He's doing really well on 2 naps, and his first nap is consistently 1.25-1.5 hours long (heaven!!); however, his second nap is consistently 30-45 minutes. We'll get a random 1 hour 2nd nap (and it doesn't seem related to how long his wake window is), but otherwise he gets one sleep cycle unless I rescue with a contact nap. I'm wondering if switching to by the clock will help with consolidating this nap?

We've tried crib hour with him, but he gets very upset; he'll only fall back asleep if he wakes up calm, but he usually wakes up crying.

Schedule - 3/3-3.5/4-4.5 (4.5 is if it's a short nap - we don't move bedtime because he's a champ at that last wake window)

Bedtime - 7:00 pm

Wakeup - between 6-6:30 am

When did you switch to BTC for your little ones? Is 6.5 months too early? Am I missing something? Or do I just have to wait until that second nap consolidates on its own like the first one?