Anyone have the ergobaby 360 with infant insert?

I have been using the Ergobaby 360 a ton with my newborn son because He is my second child and I have to be chasing around my toddler all day and he will only sleep on me.

The issue is that he’s a big dude. At a day shy of 7 weeks he was already 14lbs. The weight of the infant insert says from 7-12lbs. He’s also long and his legs keep falling out the sides and then he cries. The issue is he is not even 8 weeks and I’m worried about removing the insert because his head control is not that of a 12 week old.

Had anyone used this carrier without an infant insert (or homemade one like with a rolled blanket) for a younger baby? I just don’t want his head to be flopping all over, especially since I’m pretty active when I’m babywearing. 😕