As example, say we used three level 1 bosses versus 1 minionized level 3.
The level ones would have 40 HP each for a collective 120, Primary Attributes of 6, secondary of 4, edge 1 for a collective 3, and defenses from 12-17.
The minionized level 3 would be 15 HP each for 45 total, Primary attributes 7, secondary of 5, edge 2 split between them, and defenses 14-19.
Less HP, both each and total, higher Primary and secondary attributes, lower edge, and around 2 higher defenses, for a statistical breakdown.
Also, if you use a Boss Finale, the level one bosses would each get 2 Boss Actions from it, 6 between them.
The minionized would recieve 4.
This also introduces Boss Action sharing. The level ones would, normally, each get exactly one Boss Action, and two Finale Actions. Minionized boss, one could use one, one another, and the third none. Or, one gets both, the others none. And as each Finales, they pull from a common pool of Finale actions, so perhaps they’ll each take one, or one will take all three, or another two-one-zero split.
Also also, if the GM wishes, the Boss Actions of a fallen minionized boss can go to their compatriots.
And, of course, a good rule scales well.
3 level 5s versus 1 minionized 15.
The fives would have 75 HP, 225 combined, 16-21 for defenses, 8 for Primary, 6 for secondary, 2 edge for a collective 6 and 3 Finale each for a combined 9 beteen them.
Minionized 15 would recieve 22 HP each, round down, 66 collective, 23-28 defenses, 10 for Primary, 9 for secondary, 6 edge between them (can be split the same or differently), and a collective 7 Finale.
Still less HP, and more defense, and higher stats, normal edge actually comes out same this time, but Finale is less.
Now, what advantages does all this have?
Well, shared actions can be assigned strategically, or randomly, or depending on certain circumstances like how well the three are coordinating with one another, plus by shifting them 'round, GMs can add a new bit of unpredictability if they want.
Less health but more defenses means it takes stronger hits in absolute terms to fell them, giving a sense of resiliency, but less actual dealt damage, so any player attack that devastates the defense will more likely devastate the boss too, making them feel quite powerful as well.
Higher stats allows for more flexability when deciding what your bosses can do without needing higher levels. For example, a 15 minionized boss can use stronger boons and banes than a level 5 boss can. This also lets them hit harder with their straight attack rolls, again making the bosses feel more formidable while still being fair.
Less edge collectively leaves less round clogging by the boss, and sharing them as said above allows for the distribution itself to be malleable, even as the fight’s happening.
And for the Finale, if the GM uses much of it early on when one minionized boss is beat, the players will be less on edge themselves when the next one drops. Conversely, if the GM isn’t using that many of those Boss Actions at the felling of one, the players know that’s more that the next one might use.
Also, while this is more a personal note and personal opinion, I feel making 3 minionized bosses rather than 3 normals of one third the level is more conducive to making bosses tha fit well together, that are specifically made to go along with eachother.
End note, in case you wanted to know where I got the level ratio from, the site with the rules say a boss’ difficulty is 4X their level, so since a mimionized boss is supposed to be the equivalent of a same level regular boss, 3 normal 5 bosses are 5X4X3, 60, while 1 minionized 15 is 15X4, or still 60.
I hope that helped to clear things up to a degree!