EAlexander

Not at a computer right now, so bear with me. I don't believe there is a key modifier for this, but in the preferences, you have some control over where new objects get placed e.g. Right above the current  selected object or right below the current selected object. But.... This will affect ALL new objects, not just generators. Look around, can't remember the exact location of this in your prefs. 

You'll never get it to pure white in render, when I need that, I just add it in photoshop by adding a vignette, but going white instead of black, so the image gets pure white around the edges in a subtle fade. 
 
Not in front of a computer, so guessing on the bottle issue: can you add a Corona compositing tag to the Shadow catcher geometry and hide it from Refraction? Can't remember if that's an option in that tag. 
 
Or, render with the shadow catcher geo turned off, then render with it in and composite them together in photoshop. 
 
e. 

Hmmm - what makes this look is the thousands of stacked layers of thin film in the roll - I assume your model is not built this way.  I would probably start with the Corona frosted glass preset and play with the settings to get the "frost" level correct.  You could try adding a Clearcoat layer to get that outer sheen.  Afraid I'm away from my machine so can't play with this.  Hope that helps some.

HI,
 
You can go to FILE>Save Project with Assets and it will save a cinema file and collect all the assets from your hard drive and put them in a tex folder right next to your cinema file.  You can send this to the client if they want it as a native Cinema4d file.  You could also export the model as .OBJ or .FBX which are pretty normal formats for exchange, but then you will have to send the jpegs separately.  If you are sending the Cinema4d file - they will need Octane to render it just as you have.
 
e.