Semi-bluffing; when to do it, how much to bet

[Bigwig]

Looking for some general guidelines on when most of you try this move, and how you do it. I understand it's VERY player dependent, since many of SNG types are nearly unbluffable. But for the purposes of this discussion, assume there is a *possibility* that they will fold.

Generally, I semi-bluff in situations where I have a strong draw but am facing one of two things:
1) Bad position
-or-
2) A bet that doesn't give me the odds to flat call.

I tend to shy away from this strategy when the following factors are present:
1) Multiple players in the pot, or I suspect that they'll be multiple callers (ie, on the button with strong draw, UTG leads out a 2/3 pot bet, MP calls, and a blind is still acting behind me)
2) Against a very loose player or one that I have noted does not fold very often (full of pride type).
3) Against a stack that is significantly larger than mine.
4) In a raised pot where I am not the original aggressor (rare) and/or I suspect a big hand is likely from the bettor.
5) Whenever there has been a bet and a reraise in front of me (unless I'm pretty short and the pot now gives me the right odds to go ahead and play).

Another issue is how much to bet. I'll give two hypotheticals for comment. Let me know what you think.

1) 8 handed, blinds 25/50

All fold to BB (t2000)who calls 50
SB (t1400) calls 25
Hero (t1800) Q /images/graemlins/diamond.gifT /images/graemlins/heart.gif checks

Flop J /images/graemlins/spade.gif9 /images/graemlins/club.gif4 /images/graemlins/heart.gif

SB checks
Hero checks
Button bets 100
SB folds
Hero reraises to 300


2) 6 handed, Blinds 50/100

UTG (t1700) calls 100
MP folds
CO folds
Hero, Button (t2400) J/images/graemlins/club.gif 9/images/graemlins/club.gif calls 100
SB folds
BB (t2700) checks

Flop: Q /images/graemlins/club.gif6 /images/graemlins/diamond.gif2 /images/graemlins/club.gif

BB checks
UTG bets 150
Hero reraises to 450

Thoughts on these and semi-bluffing in general?

[Bigwig]

Erm.

[spentrent]

Is it better to semi-bluff in position or out of position?

Not an intended hijack; just seems in the spirit of your post. Plus it's a bump /images/graemlins/wink.gif.

[Big Limpin']

I'll second spentrent. You are in better shape S/B-ing when IN position. As you can take off a free card on the next street if you airball.

Perhaps you meant that you like to do it out of poosition, if you are getting all you chips in? IN that case, yeah.

[Bigwig]

Well, everything is better in position, of course. The buying a free card on fourth street when it's checked to you is a very important factor.

Perhaps out of position is good when (as you said) you're getting all your chips in the pot, or early enough in the tourney that if it fails and you don't make your draw, you're stack won't be damaged very much.