Whether you are opening booster packs, building a tournament deck, collecting Charizard cards, or organizing thousands of cards in a binder, understanding Pokmon card measurements is an important part of the hobby
Needing an engine makes Forbid a somewhat narrow card although not to the same extent as Pact of Negation
While there may not be any major issue getting your hands on Stellar Crown products due to plenty of cards and products being put into production, the probability of getting your chase card doesnt look much different than in recent sets, my friends over at TCGPlayer confirm
Pokmon Tournament Rules Handbook states that Cards that have undergone post-production alteration, [including] autographs, artwork, or other such amendments to the surface of the card, not including any official stamps applied by TPCi [are disallowed]. Like altered cards, damaged cards are also not legal for tournament play if their damage is substantial enough to potentially be visible during play
One important thing to note with Playtest cards is that, similar to silver border or Acorn cards, we have to do a little handwaving and assume that they work as intended