I've got 13,42 gearing right now and with some V-paddles in fairly wet sand it's perfect launching in 2nd. Now when I get out in some soft sand with those paddles all I do is spin, so I'm gonna have to either try different gearing or different paddles, not sure which yet.
On dirt with the same gearing I noticed that launching in 2nd I either spun too much or couldn't keep the front end down so I had to launch in 1st and play with the clutch alot.
These are all with stock ported/stroke/bore motor with just bolt-on's.