
なら seems to have a few different uses, the first of which I'm fairly comfortable with is more of a contrasting when giving an opinion on a subject brought up by another. For example:
A:温泉にいきたいんですが、どこかいい所ありませんか。
B:温泉なら、白馬がいいですよ。
In that sense, makes perfect sense to me. This second usage I'm trying to understand seems difficult, perhaps because of the way its worded in my book, so let's see how much of it I'm grasping.
As far as I know なら is essentially a derivative of ~ば and requires a certain condition in the preceding clause, and should that condition be met, the following clause occurs. First, taken from Tae Kim's site, this can be considered a "contextual conditional" and always requires a context in which the conditional occurs. For example:
みんなが行くなら、私も行く。
In this example, みんなが行く [everyone going] is the context in which the conditional 私も行く [me also going] occurs. Is this correct? I actually sat and read it several times and I want to be sure I understood it correctly.

Next, there are some restrictions to the clause preceding ~なら. This excerpt is from my grammar dictionary, which is causing me the most grief, so bare with me. When the clause preceding なら is non-past, なら cannot be used if it is nonsensical to suppose the truth of the clause preceding なら.
Now I'm a little dense in the head when it comes to grammar and literature, so I had to really stop and think about what this meant, and I think "supposing the truth" is what bothers me. Wording it differently, is it safe to assume this means, that if it does not make sense to believe the preceding clause with some uncertainty, that なら is ungrammatical? I was given three examples of where なら is ungrammatical.
10時になるなら、バスが来るはずです。
"10時になる"
If my understanding is correct, because everyday we know it will eventually be 10 o'clock, it does not make sense to be uncertain it becoming 10 o'clock. If anyone has a better explanation of what I've put here, please feel free.

あした雨が降るなら試合はないでしょう。
"あした雨が降る"
I'm a little fuzzy on this one, but looking strictly at "あした雨が降る" you cannot assume with any certainty that it will rain, so it is not correct. However, if there was preceding context, for example, of watching the weather forecast, could なら be used?
僕が行きたいなら、和子も行きたがっているはずです。
"僕が行きたい"
In this sentence, the speaker knows they want to go. Because they know, there is no need to make an assumption with some uncertainty that the speaker wants to go.
Regarding the third sentence, however, they give an example that looks almost similar but is considered grammatical.
僕が行きたいなら、誰にも言わずに一人で行くよ。
According to my grammar dictionary, "僕が行きたい" is counter factual in this example, but I'm not quite sure what they mean by that. If anyone can think of another example of this, I'd be very grateful.
Looking over this post I almost feel more confused than when I started, but I really want to make this sink in. I have a habit of over complicating little things, so I do apologize if I'm making a big case out of nothing. Also if I haven't made any sense at all, just let me know and I'll try again.

Thank you in advance to any and all replies.