Build over the first three sets to a challenging but manageable weight, leaving two solid reps in the tank. Use 85-90% of that weight for the fourth and fifth sets.
As Far As Possible in 12 Minutes:
3 Wall Ball, 20#/ to 10'/14# to 9'
3 Box Jump Overs, 24"/20"
6 Wall Ball
6 Box Jump Overs
9 Wall Ball
9 Box Jump Overs etc
Extra Work: Bike, Run, or Row
30:00 @ 7-8
Select the modality which is the easiest for you to control you pace and heart rate. This should be hard work, but far from maximal. You should be able to speak in brief phrases but not hold a conversation.