RE: What planes faster...?
I recently got a go 139 and can get it planing with a 6.6 metre sail in about 6-7 knots. I hang a lot of my weight on the boom while being neer the mast base and then pump. I get going then move back making sure not to push down on either rail. The go 139 also comes with a 480 fin as well as a beginner 410 fin. I am a sailer who has sailed 8 times and for my eigth time my cousins were up at my trailer and they wanted to see me go. there was around 5 knots so I went out. I practiced some flip 360s and sail body 360s and then the wind picked up a bit to around 6 knots gusting to 8 at the most. I could get planing easily with the go. This time was my first time to also use the gos 480 race fin. What a difference!!!!!!! I could plane way eisier. I am thinking of getting a 50 cm fin or maybe a 54 cm fin to get planing even earlier.
I suggest the go 139 more than anything as I am 16 and way 130 pounds (57 kg i think) with the tufskin and the two fins it is a great board to get planing in light winds. Think of the winds I could get planing in with a 9.0!
I might even go with the 2006 model. That is the one I got and they say they didn't really change it that much. I have used it with a 5.0 and 6.6 metre sail. In around 17-20 knots mostly. Its a fun board which as the website says, jibes really well too.
Hope this helps,