I understand what you are wanting to achieve. I am an experienced wake boarder, and due to work relocation have just sold my wake boarding boat with tower etc, and got a small rib which is more suited to where we live now.
I'd expect the pole you are looking to install would be ok mounted in front of the outboard, but personally I'd want some small struts from towards the top of the pole mounted forwards, to counter the pull created by the boarder on the back.
I'm not sure what level of wake boarding you are doing, but you will be limited to what he rider can do due to the size of the wake, and they will drag the RIB around if they start cutting hard etc.
This discussion reminds me of what my Dad told me once, a man needs several boats, as one boat won't do everything he wants/needs...