Now you can play purely "on time" set MCTS Iterations (Total) = 1 000 000
Time Limit per Evaluation Batch = 15 000
your move should be 15s (little more) (you will see how many iters your computer does for 15 seconds)
Now it consistently thinks for about twice the time limit, which is perfectly fine, but I can't set the iteration limit that high because it starts freezing my browser again. And even at 150K iterations it doesn't seem any smarter than at 5K.
You may set 1 000 000 iterations in options but what these numbers show is what actually was calculated, in this case:
9951 of 10000 moves. If you set low time you will never get to 1 000 000, it will stop on the time.
You may look at the Help there are tips there.