I like him. Very entertaining fighter, got a lot of heart and despite having a patchy record on paper, he's pretty good. A matchup against Ola Afolabi would be a good choice or Mchunu who seems beatable. Both would be good matches to hopefully set up a world title shot.
Cleverly would be a good choice. Maybe too high risk/low reward for Clev though, I can't see his team taking it.
I don't think Mckenzie gets higher than European honours, that belt is emminently winnable and would add nicely to his current belts. I'd like to see him win the Londsdale outright as well...
Ask Vince Clev on facebook He told me about two years ago that Adam Booth pulled out George Groves from a sparring session with Nathan because he was getting such a beating.