A3 : Darkness-type decks struggle in the meta primarily due to the introduction of the new Golem card in the Mythical Island mini-set
Play 3:2, 3:1 or 2:1 of White:Black, depending on build and preference
While there may be stronger cards available for pure ATK boosting or Fusion Summoning in other archetypes, Soul Union's versatility and potential for explosive plays make it a viable option that could see play in a dedicated Elemental HERO deck
As for the best of the new creatures, O'aka, Traveling Merchant turns your excess counters into carddraw, and Maester Seymour grows creatures of your choice as you grow him
Corner rounding is commonly referenced around 1/8 inch (roughly 3 mm, sometimes listed closer to 3.5 mm depending on the spec source)
The incoming DBA students are: Andrew J