The fling is fun! Have you tried using the Hi-start? Oh boy is that even more fun!! You get a heck of a lot more glide time with the hi-start, you can also discover more thermal activity at the higher altitude. Hand launching low to the ground you miss a lot of potential updrafts. I am far from a sailplane expert, but when you launch from a high start, and the Fling maintains a certain altitude for long periods of time (5-6 mins) you know there is some kind of force keeping it up there (i.e. Thermal)...

Have fun, and wise choice on the Fling!!

~Noah