Hrqls: Yes, you set the playing strength at Settings/Players. Just click on expert and select World Class. You can do this for both chequer play and cube decisions. Then do the same under Settings/Analysis and Settings/Evaluation. Experiment a bit if you like and when you're happy click on Settings/Save settings. Otherwise next time you run it, you'll be back where you started.
1-ply is a compromise between speed and ability. Just don't trust it too much.
(hide) If you don't want other users to know what you are doing you can change into cloak mode in Settings (paying members only). (pauloaguia) (show all tips)