Cluster sets are always something that, when done properly, can get you a massive pump and some really good work in. As any other means of training, these sets, in particular, can bite you in the ass real quick. What you think you can do throughout the total amount of clusters is very skewed until you are balls deep in about your second or third and by then it is too late, you have already chosen the weight and you are either going to finish or be a little B**** and fail, this is how 275 had me looking...

Pushups – 3x15: BW
BB Bench press – 3x3 with 15 seconds rest between sets (then rest 1:30), then another 3x3 with 15 seconds rest (rest 1:30), then another 3x3 with 15 seconds rest: 275
DB Incline – 4x8-10: 70
superset with
Chain fly – 4x10: 2 chains
DB Lateral raises – 4x8 heavy
Superset with
Banded side laterals – 4x15, even if they are partial reps, get a lot of blood in there
Sling shot pushups – 100 total