Well, it's taken ages, including a second or third set of attempts to get to 2off, tricky.
Edit:-----------------------------------
I thought I'd tried every possible set of moves many times, till I went through all the possibilities and found one I hadn't tried and it worked. I think I thought it couldn't possibly work.
Another "elementary" level which I'd say was closer to junior high. First set of tries and I couldn't get it. I just needed to take a lot of care in minimising steps and not moving some boxes too early.
I started at 8off then worked myself down to 2off and finally the 97. I think what needs to happen is relatively obvious, but it needs care to hone down to the fewest steps.
Insights