Interesting observation, that the game only goes to 4 (officially). The game was taught to my wife and me at a gaming night at one of our FLGS, so I never read the rules. I did ask specifically if the game would accommodate 5 players, and was told yes. I never even looked at the box.
I did enjoy the games I played, though indeed there were many times that there was not a given color token on the board. Out of 5 players, there usually not more than 3 or four cards on reserve across the 5 hands. I only realized that that might be unusual in game three or four, when someone went to reserve a third card for themselves. I protested that the limit was 2 per player, because that was what I had been told for that very first game. The book was pulled out, and it apparently does say the limit is three reserved cards.
Thanks for the tips. They may help. I intend to buy this game for a niece and nephew for Christmas, and take it on a cruise with us. It's is an interesting game.