Hi, for SJT - the same amber jack assessment like other firms. The pillars are different - client, firm, people - marked out of 10 each! Keep the firms core values of the firm and skills needed in a trainee in mind and answer accordingly. Be yourself and you will be fine
For written ques (2 ques - 500 words each) - don’t think you should worry too much as the written element is untimed and you can keep coming back to it. I took an hour or more to write them and still progressed so I do not think they take time into consideration!
You will only get ur feedback report once you finish the complete assessment including writing part.
Hope this helps!