Save the trouble of dragging the glider out, but go to Estrella anyway and fly with Jason in the Fox. If it does turn out to be a soaring day, you can try your luck at thermalling inverted! And if it is not soarable, you are definitely not doing just a sled ride.

Great folks there and they do the best job I have ever seen at any gliding (or powered) operation of recognizing that safety is important and needs to be considered, but you are a CUSTOMER there to have FUN.