Hi Joe,
Sorry mate, the wind didn't come in until after 4pm

With regard to the XR4, a lot of the answer to your question is dependent upon your weight, the board you ride and the skills you possess.
The XR4 is an excellent kite and has me powered in 25 knots on a 135 twin tip easily and I weigh 95kg, so I'm guessing it would go close ....
Drop into the shop and pick it up for a demo, it looks to be windy all week.
DM