Ideally, it's better not to use normalization if you can avoid it. If you record your track with enough volume, you probably won't need it. But sometimes I record a track too low, and even if I push the fader all the way up it's still not loud enough. In this case I usually have to normalize it. The main issue with normalization is that it will introduce very subtle roundoff errors. But in practice, people like us won't hear the difference anyway. I don't know that it makes a big difference to what level you normalize. Ideally, you'd want to use whole numbers. For example, you'd want to exactly double or triple the audio values to avoid roundoff error. But I don't know if many programs let you control it that way. Anyway, it's really not worth worrying about.
You do not have to use as many channels as audio tracks. You can have two tracks that use the same channel. As long as the sound on the two tracks doesn't overlap there isn't a problem. For example, you might have a background harmony on track 1 that only occurs on the chorus. Let's say that track is assigned to channel 1. Also, say you want to have a cowbell playing during the verses but not during the chorus. You can create a new track 2 with the cowbell on it and assign that track to channel 1 as well. As long as the parts don't overlap you should be OK. One thing to remember is that the mixer fader on channel 1 now controls both the cowbell (during the verse) and the background harmony (during the chorus).
I don't own Gigasampler so I don't know about that.
Later versions of Cubase will (obviously) have more bug fixes. You'll probably have to try it to see if you particular problem got fixed. Once in a while you hear someone complain that a later version got worse, but not very often. It's almost always better to get a later version when it's only a minor version number increase. I think 3.75 was the one that added the Rocket Power thing. If you don't need that then you might want to just get the version before that. Was it 3.73? I forget.
I usually edit one audio file at a time. I don't have an answer for this one.
Jim
