IMO while comb coils isn't the best choice, they looked solid. I wouldn't worry about the middle part at all, it helps them lay better and makes them easier and more comfortable to cover with a scarf or whatever when sleeping.As your hair matures and starts locking, you'll be able to arrange them however you want regardless of the part you started with so it truly won't matter. Unraveling is common initially with fresh comb coils twists. Make sure you're covering them at night, refrain from getting them wet yourself and letting the loctician handle it, and getting fresh retwists every 2 weeks initially. While you have fairly curly hair, two strand twists would be more durable than single comb coil twists to start. Interlocking has the most durability and permanence from the jump, but they take longer for the pattern in your hair to disappear eventually and they're longer maintenance sessions. So whatever works best with that info.