One of the objectives is making NU great again; Quilava, Graveler, Ivysaur,... nobody plays these type of combats and they are mostly uncommon,
so I propose this type of leveling in addition to 50 and 100.
Basically, an item which function is stopping the increase of level, no matter how many Pokemon your Pokemon fight against after being put this item in it.
https://forums.pokemmo.eu/index.php?/topic/61176-lc-little-cup-general-guide/
But I don't mean this, but a simple reduction of level to the mentioned ones, OR, an applied medium between the levels of both trainers.
Level 30 by example, or level 5, reducing the stats to the required levels.
Or even making an automatic media between the levels of the duelists, f. ex.: one is level 100, the other is 60; automatically the level set is 80 between both of them.