I think Marco is named as Macro in your post and it's Sentomaru, just so you can fix.
BTW, good thread!
One thing about rating character strength in general is that it actually almost never reflect reality.
Like, Luffy is in Level 5 and Crocodile is in Level 7, but Luffy has already defeated him.
Also, some characters strength are based on pure speculation, i.e Do Flamingo, we never really saw a real fight with him. Although I agree that he is around at Level 8.
And one more thing, IMO, the WB Captain and the Shichibukai are on the same level, except Moria.
I don't have a freaking idea about the VA, I mean they are supposed to have the same abilities as the CP9, (Rokushiki, maybe?), but Luffy beat the strongest member of all history within the Cipher Pol., Rob Lucci, so for me Lucci, should be around the same level as a VA.
So, I agree with almost everything, in a normal situation I think it is pretty much the levels of strength in OP.
Note: Can you put Roger and WB on Level 11, I don't have a very good reason for this, but they're out of this world, I mean, like it was said in the manga, excluding them, the rest was just silver medalists.