18.5 = 12.5 = 11.6

CrossFit loves to re-test!
We have done this before – if you are good at both thrusters and chest to bar you will need to chew through concrete once minute 4 passes.  If you struggle with one moment, but are good at the other, you will need to press where you are strong and catch your breath were you are less confident.
But – breathing is huge here.  You will need to warm up so you are breathing heavy and all hot and sweaty when you start.  From the start, I recommend breathing  big and deep early.  Once your blood turns to acid, breathing will help you flush more efficiently.
I recommend: for 10-15 minutes, row 250, lunge down and back, press DB 5 times, 3-5 big pulls.  Do this at a nice easy pace until you begin to breath heavy.
I do not recommend going huge on sets here.  If you know yourself, take planned breaks, and use the clock, not your head, to pick up the bar.  If you go by feel, and blow up, you may find yourself standing around.  The pullups are much easier to break, as you get back on the bar faster.  Even quick singles are pretty good here.
For thrusters, small sets of 5 are good.  I am going to try to stick with no more than 9s, but never let the bar lay there for too long.

Workout 18.5 = 12.5 = 11.6
Complete as many reps as possible in 7 minutes of:
3 thrusters
3 chest-to-bar pull-ups
6 thrusters
6 chest-to-bar pull-ups
9 thrusters
9 chest-to-bar pull-ups
12 thrusters
12 chest-to-bar pull-ups
15 thrusters
15 chest-to-bar pull-ups
18 thrusters
18 chest-to-bar pull-ups