Partially disagree with your conclusion MasterSeedy. The offense bonus from mods is applied BEFORE the unique kicks in. Therefore you are getting an additional 15% of 15% (2.25%) offense every time the unique is triggered with an offense set compared to the CD set. The math says they are extremely close and the decision should come down to which mods have better secondaries.
You should definitely be using a CD triangle.
Given identical mods except for set bonus, damage from the offense set is 99.46% that of a CD set once 100% CC has been reached (3-5 defeats) and does not change with increasing defeats (relative damage reaches an equilibrium). Prior to this the offense set is better. Hence why the in game recommendation is offense since most PVP battles (though NS fights are often an exception) are basically decided after 3-5 defeats. Not to mention if your opponent throws on an anti-crit arrow it’s going to delay the tiny benefit of the CD set even more.
If you are min/maxing for raids, then CD is minutely better. In basically all other circumstances they are for all intents and purposes identical. The mods with the better secondaries should be the deciding factor.