Thanks for posting this info.
We were able to get up there over the weekend, and it was great to skate on Tenaya Lake!
There were quite a few people there with the same (or better) ideas. One large group were sitting on chairs on the ice, had coolers with beer, and were watching their families playing hockey. They had brought all the gear including goals.
A ranger had recommended the eastern end of the lake. It did seem to be smoother at that end.
The ice was remarkably clear. In the shade, it was possible to see through the ice to the lake bottom.