Okay. I'll take a stab at it. There are a lot of penalty situations
in 10/7 DB, but I think that the most important and frequent are as
follows.
First, there are several situations where it is better to hold Ace
and an unsuited high card rather than Ace alone. Generally, you
should prefer Ace and an unsuited high card unless all discards are
6 or higher. Or, if you have non-suited 10. Or, if the Ace has a
flush penalty.
Second, it is better to keep KQ or KJ suited (rather than a 3 card
flush with 2 high cards) unless there is a straight penalty to the
KQ or KJ.
Likewise, it is better to keep KQ or KJ unsuited (rather than a 3
card flush with 1 high card) unless there is a straight penalty to
the KQ or KJ.
Third, (my personal favourite), it is usually better to keep a 3
card double inside SF with no high cards rather than a single high
card. But, you should prefer an Ace if there is a straight penalty
for the SF. And, you should prefer a J if there is a straight
penalty for the SF, unless the straight penalty is the same suit as
the J.