The place of Int. Wind Girder

[69020211]

Hi all friends

I am calculating for the intermediate wind girder in a open-top storage tank.

the tank needed one wind girder.

Max. height of the unstiffened shell, H1=3.3 m
Height of the transformed shell, Htr=6.2 m

i would like to know, which place should be the girder installed on the shell.(on transformed shell)
in 3.3m below the top course or in the 3.1(=6.2/2)in the middle.

because in section 5.9.7.3.1 in API 650 has written:

"For equal stability above and below the intermediate wind girder, the girder should be located at the mid-height of the transformed shell"

Thanks
Ahmed