hi Sanjay
I was in the same position as you
my biggest kite was a 13m and wanted a board that was something more than a big plank.
Ended up getting a Shinn King George 140 x 46
sound like a strange size but it works

gets me going at about 12 knots - 13m kite (I'm 85kgs)
been out on it at 20 knots
it works well, as swapping boards when the wind fills in is easier (and Cheaper) than swapping the Kite
I even use it with my 9m kite (15-16 knots with a few holes) then just come in and grab my other board
Again I didnt want to be the first out just wanted a board with good characteristics