This is a couple of questions to the devs, to clarify the secrecy rules further.

Is it okay for a player to announce a rough percentage of what he can aid towards a skill check, or is this against the spirit of the rule?

Can the players talk about what they are putting in secretly, not in front of the Cylons, as long as the players are aware of the number of cards they are putting in?

We just want to make sure we're keeping true to the spirit of the game.

I'd say that a percentage is more accurate than saying "a little" or "a lot", so it's probably better not to say such things, unless your group has trouble passing skill checks. My groups house rule is that you cannot say anything beyond the number of cards you intend to play.

You cannot discuss anything in secret - all discussion must take place in front of all the players.

Announcing percentages is wandering off into 'code' land. And by that, I mean that while you are not announcing the exact value of the card (i.e. some number between one and five, and a colour), you're indirectly relating an exact value. For example;

1 - Barely helping

2 - A little bit

3 - Medium

4 - Helping a lot

5 - A ton

Many groups end up with these conventions without realizing it; I suspect it is part of our urge to communicate as humans. If you're having trouble with secrecy rules and card values, refer to the FAQ, which clarifies exactly how one should play if they're having difficulty finding the line on secrecy. My group certainly did, and we found the FAQ very helpful.

May I know if it is possible for a player to NOT take part at all in a skill check? As in he does not throw in a single card.

It's pretty obvious when someone doesn't add to a skill check. It's kinda hard to hide it when it happens.

Wanderer999 said:

Players do not have to put cards into skill checks - some players card sets will be incompatible with making certain skill checks pass, some players may be out of cards because of discards or play.