That's made my brain hurt - trying to understand dynamic soaring. SP250, you mention curl over in the lee of the slope, and I'd kinda convinced myself of how it works. But on further reading, the mechanics of DS seem to rely on two different air velocities, such as between the dead air in the shelter behind the hill, and the wind blowing horizontally (more or less) off the top of the hill. Identifying the boundary layer between said dead area and the wind seems key to successful DS, according to the article below. So I'm a bit confused by that.
The gliding club, where I fly, has a long ridge (about 300 to 350 feet high) that works well in a stiff westerly. In an easterly, we're in the lee of the hill, and that is usually proper rubbish. Occasionally, in an easterly, we do find a band of lift, parallel to the ridge, but a few hundred metres downwind of it. But I'm not aware of any hint of lift close to the ridge in an easterly - maybe we just can't get close enough. Having said that, some of the guys have found lift high above and inexplicably close to the lee of mountains.
Interesting that modern gliders have tanks in the wings and tail that can be filled with water to increase wing loading so we can fly faster cross country. So I get the bit about DS gliders needing to be very heavy.
https://www.rc-airplane-world.com/dynamic-soaring.html