Just ran across this article by John Heiney, one of the best aerobatic HG pilots ever. Even if you learned about this from flying GA or Aerobatic airplanes, this explanation from the HG perspective is worth reading.
Not all ridge lift is created the same - for sure. POTM on the south side has a smooth lip and is easy to get close to the hill without too much worries. North side has all of these gulley cuts in the lip and also has more thermal gusts. I watched an eastern pilot familiar with ‘smooth’ ridge soaring getting far too close to the hill and eventually stepped into a gulley pocket which turned him into the hill and caught his leading edge in the brush. Fortunately it didn’t result in injury, and we only had to cart the broken glider out. Lessons learned!