Even a tiny deviation in MTG card dimensions can disqualify you from a tournament or spell the difference between hundreds of dollars in resale value
Heres a table with these presumptions, and the two possible distributions
Lets say X=5
The tournament wasnt large, but it was full of stock decks from what I saw: Mono-Red, Green Black, Green White, a couple Teferi, a Mono-Blue player, etc
In Pioneer, Underworld Breach saw heavy play in Lotus Field Combo as it made the strategy unfair and consistent
However, if you can boost his strength high enough that he wins skirmishes (generally using possessions, Noble Leaders (7R112) , The Last Alliance of Elves and Men (1R49) , or Merry, Friend to Sam (1R302) ), he can discard those minions for you, similar to the way he's used as ring-bearer