"Best" is pretty subjective, but I think Deluxe has the most options for concave and good shapes - they for sure run at least one twin tail shape that Ishod rides. But Baker offers multiple concaves with decent shapes, and if we are talking JUST shape varieties, polar has a lot. Weird shapes, Welcome and Herion.
Obviously none of this takes into consideration team, content, graphics, contributions back to skating and skaters... too many variables.
Pressing 4 decks at once leaves 4 different degrees of steepness to the concave, so yea, single pressing is better for uniformed concave. Ive heard that Deluxe has special marking on the top ply that indicates which number the deck is in the mold stack. the top being the steepest and the bottom being the mellowest... Im pretty sure. Someone please correct me if Im wrong.