The 7x7 board

The 7x7 board is the medium board. A round on it starts with a seed word across the middle row, and you make 6 plays from a rack of 7.

Difficulty
Medium
Cells
49
Premium squares
8 (17% of the board)
Exotic square types
3 of the 14, chosen per board
Plays
6
Tiles in the bag
20
Rack
7 tiles

Which premium squares a board carries, and where, changes from puzzle to puzzle; the counts above do not.