No one can really answer it as it depends on what you're doing...

What weapon/skills and environment (PvE or PvP) dungeons, trials, solo, dueling

What's your goal in wearing both?

It matters a lot as for one generating an ultimate primarily depends on the weapon and your style of play as well as where you're playing.

You mention magic night blade and you talk about meteor and other nightblade things.

In a Trial there is often more time to build up ultimates BUt that depends upon what ultimate and how viable it is in a given situation.

Same applies to dungeons, PvP or solo play.

You mention single target....and magic nightblade....are you playing in melee range or using ranged weapons. What's on the primary bar and secondary bar as well as the skills on each really make a huge determination.

You also have to consider what other full or partial set you'd be using.

I personally think all those matter a whole lot. In my opinion, neither are good for a magic nightblade but that's purely based on how I play mine which ch is with dual swords and a staff. I don't use meteor ever on my nightblade but now the staff ultimate IMO is pretty good.
I don't see minor force or minor heroism as beneficial but perhaps some of the other bonuses would be good. I'm not familiar with the set tho as it's not something that catches my eye.

I usually wear gear for a 5 piece and then either a monster or 4 piece bonus. I try to get the most of the better set and supplement with partial of another set.

Again....all of this is ssubjective as I play different than you perhaps, and I don't think my magic nightblade is considered "good" but it's enjoyable for me.

The question always boils down to, "what are you trading out to get these sets?" Can they work? yeah. But they won't work better than another setup for dps.

I don't know the 2-4 set bonuses, but there's a good chance that they benefit either stam or mag which means they are more or less useless to either stam or mag. Maybe not a deal breaker but worth noting.

Now, in order to fit either of these into your build, you will probably end up using jewelry if you are running TBS for trials. Giving up jewelry means giving up the damage bonuses of VO/Infall/Moondancer, and you'd still need to give up 2 more slots either for weapons or your monster helm slots.

Monster sets can give pretty solid dps in the right conditions. Probably on the order of 2-10k depending on the set and conditions. So giving them up likely is not ideal. And giving up the 5% from the trial sets is a 5% that cannot be gained elsewhere.

Stamina rotations almost always include beast trap because the dot is pretty powerful AND it reapplies itself AND I hear it doesn't consume a cruel flurry empower but still benefits from the effect AND it grants minor force.

I hear that mag templars end up running Mystic Guard (stalwart gives minor vitality - 8% healing) to gain minor force for themselves AND another group member.

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Minor Heroism only grants 1 ult every 1.5 seconds, and you may have gotten it backwards. Either way, many of the same arguments apply to this set. The increase in ult gain and the following ult casts would almost definitely be beat out by the losses from forgoing other sets.

The other thing that's perhaps obvious but often overlooked, % increases only work well if you are already dealing a lot of damage. I just run my trial healer setup with combat prayer, infall, warhorn, spc, etc. And the dps increase for low dps groups isn't even worth mentioning, but a high dps group will just obliterate everything when empowered by that setup. The same obviously applies with these sets.