This was very hard for me, to see. Was at 374, first try. Next try 400. Then slowly getting down, and somehow got it under 200. After that it still took me quite some more tries to get it under 170. After that it went a bit faster. Got stuck at 140 for a short while, just before solving.
After solving it doesn't seem so hard, anymore. :)
Excellent logic! I had a great time even as I was convinced that I had tried every option, and thinking about what I needed led me to a wonderful realization.
Insights