Trim tab placement

[72potter20]

I've been meaning to put tabs on my boat for some time now. A local marine supply had a great deal on a set of Bennett m80's so I picked up a set.

After doing some researching it appears that the preferred mounting spot is on the outer most step. My transom will not allow this unless I do some major relocating of various things.

They will however fit perfectly on the middle step. Has anyone mounted tabs here? Should I go ahead and put them there or go ahead with relocations? Relocating would mean many new holes drilled in the transom