Before the cards are divided between the players, discard the top 15 to 20.
That way, a player who knows the deck cannot assume his opponent has all the cards that he himself does not!
Place all the cards in the middle of the table in one deck, face down. Both players draw their hand of five cards, and all replacements, from this deck. (This is how the original French Tempete sur l'Echiquier worked).
In this version, any time you do not play a card on your opponent's turn, you may discard and draw a replacement. You may still discard on your own turn as well.
If you use up all the cards, just reshuffle the discards.
If one player is stronger than the other at regular chess, give the less-experienced player more points to work with.
A rated player with a deck of 80 to 100 points might be a fair match for an unrated player with 200 points. If it's still no contest, increase the handicap . ..
Each player starts with his own Knightmare Chess set, and creates a deck from his own cards. This way, you can be sure of getting the cards you want . . . but your foe may have some of the same ones.
If each player has more than one set of Knightmare Chess cards to work from, decks can be even more specialized. You may have several copies of some cards. But a card with a * beside its point value must be unique; no deck may contain more than one of any such card.