That's a lot of text.

Though, Ostarion, you're wrong. That's not how it works. The Logia does scale with your own power, as showed by Ace whom oringially was getting mauled by Whitebeard when he joined the crew. And by the time of Marineford Ace was third strongest on his crew. His powerlevel increased, he didn't just become smarter and more used to his power.

Akainu was stronger than Ace, which is why he could kill Ace. Not because Akainu's power was more powerful than his.

Though: Personally, I would suggest doing an elemental Paramecia instead of a logia power mostly due to the Logia power being very powerful and usually considered to be on par with Mythical Zoans.