I ask because there are many applications to clusters. The original one of 1-1-1-1-1 (5-6 reps with 10 sec of rest between reps) with about your 3RM (90%), which is more a strength and size method. It is one of my favorite ways of training but it is very draining.
Why? Because the volume of very intensity work exceeds the "optimal" range for an exercise. According to the Prilepin chart, with 90%+ weights the optimal number of repetitions (total reps, not reps per set) is 7 and the effective range of 4-10 total reps.
If you do a cluster set of 5 reps it means at the most 2 sets. So if you do 3-4 which is a normal set-up you greatly exceed what is optimal.
HOWEVER you CAN exceed the optimal zone for short period. That will work well as a "blitz" and will give you solid results in strength gains for 2-3 weeks, maybe 4 if recovery is good. But past that your gains will stagnate because of the excessive volume of high intensity work.
OK... the cluster variation you are talking about isn't the original one. I personally call it either clusters of doubles (micro sets of 2) or clusters of triples (micro sets of 3). Which is a better method for size than original clusters. But it still represents a very intense training methods that I would personally not use for more than 4 weeks.