this did not seem to be a true expert. either that or i screwed up but was luckily correct.
Difficulty score 48. No green. I definitely needed a couple expert tricks. And my scoring program agrees with the expert rating. But it did fall into place nicely at the end.
skyscrapper makes it. greens galore
Did it no green. Easy till close enough to the end to follow in my head to a contradiction. But at that point I made a mistake, thinking I had started from a binary cell -- it actually had three possibilities.