Ive just been trying the Shinn Monk and I am very impressed with the board.
Great up wind, great early planning, good POP and allround fun.
I'm waiting for my 133 x 41

but with winds of 10 -15 knt and 70 kgs you could look at the 135 x 42 or maybe the 135 x 44.
I was out on a 135 x 44, 8m kite and 15-18knts and it felt great, not too wide, easy to hold an edge, great fun and everyone else was on 11s and 12s!

Speak to Duncan or Arron and get them to post a board up.
if you don't like it, want a brand new one or its the wrong size, it will cost you the post back
contact is www.shinnworldoz.com