Putting it yet another way; does the dps/heal boost from the set bonus overcome the difference in stats from 224 to 216 armoring, mods, and enhancements. Now my comment--
There are a few problems with this question.
1. The 224 gear is supposedly optimized for one spec and is being used on another. Unless the difference is more than all the set bonus boosts, one would have to find 36 answers to your question. [n(n+1)/2; n=8 (It should be n=18+n=3 but so many of the specs are close to 5.5 crit : 4 alac that I am arbitrarily choosing to just use ACs)]
2. Many set boni affect rotations through lower cds and energy costs, by sacrificing the correct set bonus you are in essence learning a different rotation and the most important thing in getting good numbers is knowing your class.
3. Because of the prevalence of Mk-2 drops and 220 token drops gained on your main(the 224) you should have more than enough mods and enhancements to gear your second with 216 armorings and low endurance 220 mods and enhancements)
Now a newb at theory-crafting will try to answer the question even with the problems listed without recalculating everything with Bant's method.--
Stat budget (Master, Power, Crit, Acc, & Alacrity) of 224 gear is 11087 and 10232 for 216. This is an increase of 855 or an 8.36% increase and translates to on average 474 more dps or a 7.81% increase. However, you have to remove the bonus that comes from the non-legacied items--
73 stats from the earpiece, two implants, MH, and OH and 8 from each relic for a total of 381.
Subtract that from the 855 increase and you get 474. I do not know what the correct denominator should be, but using the full stat budget, 474 is an increase of 4.63%. (I know mh and oh can be legacied, but they should not be used to make this determination because if the class can use it it should and if it can't, it won't matter)
(Actually a more precise method would be to find the stat increase the other way. So 73*5+28=393 or 3.84%, I'll ignore this however, since I thought about it after writing the post, but it would only strengthen my case.)
Next, I'll guesstimate the avg increase in dps from the increased stats to 4% because the stat budget increase is not a 1:1 dps increase and Relic and Force/tech power should not be included.
Without knowing or researching the actual set boni increases. I will use the dev's stated goal (I know risky) of a 5% increase.
In summary, 5% and correct rotation > 4%.