So, long story short: I've been playing with your mod on 1.12.2 and during some play-tests (for my modpack) i've noticed that there is 2 different versions of maelstrom gauntlet, regular one and alternative. It appears that alternative has 2 phases, but it doesnt appear in the crimson kingdom arena.
So, i'd like to ask, is there a way i could replace the regular one with alternative? I can understand a few things about coding so i may try to edit the structure itself and then compile the mod, but in case there's any other way to do it, please tell me, or guide me wich structure should i edit. Thank you
P.s. i've looked in the configs, but didnt notice anything that could help me

Well, i've figured it out myself, just had to replace data block in structure with the edited spawner block. Though more correct way would be replacing boss entity data, but i couldn't find it. Thank you anyway for such a good mod
(For everyone who will want to do the same or simillar, the structure with boss is in
"assets/mm/structures/crimson_kingdom/"
And the file is "crimson_kingdom_26_28.nbt" with spawner (data block in this case) is being 1896th entry.