618T Structure Scan transducer location

[mdsn]

I am mounting a SS 'ducer to a 618T. I am told the factory direct mounts them to the horizontal step.
I have also heard concerns about leaky screws and the inability to level the ducer when direct screwed to the step.
What do you guys think the best location and best mounting method is?
Thanks

[SDRanger621]

I'm about to do the same thing on a 620. I would possibly recommend mounting it a transducer board to eliminate all the holes.