Blue Efficacy said:
Playing spot 7 on a full table on a DD game with 20-25 cards cut off, being able to see the cards can make a difference that cannot be discounted.
A seven-handed DD game is not a good animal. Even with the unusual pen you mentioned, you'll get in 3-to-4 rounds per shuffle, making 30% of your hands come off the top of a full pack. Your final bet before the shuffle will be placed with about 45 cards remaining, so the
effective pen isn't nearly as good as it sounds in this very s-l-o-w game.
If you were playing that same spot in a face-down game, there would probably be 8 hole cards you couldn't see before playing your hand.
If the dealer's up-card is 7 or higher and those players have hit one time, count their hole cards as neutral. If they have hit twice, count them as a +1 or +2 depending on the size of the hit cards. If they stayed pat, give them about a -1.
If the dealer's up-card is 6 or lower and they have hit at all, give them a +2. If they stayed pat, disregard their hole cards until you see them. All this is just done on a temporary "fudging" basis in case it might affect your index decision. Save the official RC for actually viewing the cards.
Don't forget that on average, the sum of those unseen cards will be about zero. If you could literally see those 8 cards before playing your hand, you're merely updating your index decisions 8 cards deeper into the double deck -- nothing more, nothing less.
Some other things not mentioned about a crowded DD game is that with 20 or more cards dealt between rounds, the TC will vary widely from round to round. Your resulting bet sizes will have to be de-optimized too much, and then, you'll only get three or four rounds per shuffle in an otherwise excellent 75% pen game.
Now in a 60% three handed game, you'll get six rounds in and will have more flexibility in massaging your bets around. You'll still be sizing your last bet with about 50 cards remaining and there are likely to be maybe just two hole cards you'll need to infer. Plus, you'll get in roughly twice as many hands per hour.