Mike Hessington wrote:

But if you want to fly long tasks in the wave you will
occasionally need to fly over 8/8 cloud. Fact.

This could be argued, but I'm not going to do so. As I said in an
earlier post: If you are willing to put yourself in that situation, then
by all means install needle and ball. There is no way to bring a
slippery glider safely down without, and there is no substitute. All
those GPS gizmos are nice, but far too slow.

And, while we are at it, be sure thre is still some VMC left below the
cloud deck, and there is a reachable landing spot. After all, waves tend
to form over mountains. But then, this may be a question of temperament.
I've heard that there are even people who enjoy night flying in a light
single.

Stefan