"only XL-3"

The host generates a pair of random castles using a special button. Immediately after generation, each player can request a regeneration for 500 coins as a rollback to the opponent. If, during the regeneration, at least one castle is repeated, then the same player can (but is not obligated) request a free regeneration until a new pair of castles appears. The rollback cannot exceed 10,000 coins. After the bidding for the castle, the bidding for the color begins.
For example, after all the bidding, the result is a red Castle on a blue swamp. The Castle was bought for 2000, and the color for 1000. The total amount of 3000 is transferred by the host to the players' accounts before the start of the game using a special button (in HW Rules 1.38) as follows: opposite the red player, it puts the value -3000, and opposite the blue player, 3000.