I did mine 2 days ago, it was always my worst score on medify where I always averaged 50.3% for QR but ended up with 730 on the day even though I didn't have time to put an answer to 2 questions and I had guessed the last 12 questions because I had 2 minutes left. i still don't know how I got the 730 in that section though, but everyone seems to be getting 700-800+ in that section this year so I think the mean average and deciles are going to be higher this year because of that (much like what happened to DA in 2013 where it averaged something like 750+ for the people who took it).
I just tried to practise with timings and common questions, e.g. % change, working out mean averages of 6 or more complicated numbers with the stupid online calculator in under 40 seconds etc. My friend who got 830 literally did this too, but put in more hours than me (she finished all the stems for QR on medify) even though she did a mock the night before and got predicted 600.
The actual questions are like Medify but a bit more easier, the maths isn't hard (Nobody I know who got 700-800 did any maths revision or bbc bitesize) but it's really tight with time so I'd suggest practising so many timed sections (I used the 40 timed sections in medify).
Good luck x