You can of course ask the tutors by using the messaging facility which you can find on the Wiztut home page or on the blogs of tutors or in your student panel. You can also refer to the blog of your chosen tutor(s) and and by clicking on the relevant button see the working calendar for each tutor. However please remember that not all tutors organise their calendars methodically and hence contacting a tutor to confirm his/her availability will still be a suggested method.
Simply put, you can use Wiztut messaging to find out the tutors' availability or refer to their blogs and lookup their availabilities via their working calendar.