Hi verdaccio,So many questions
I think I can answer two 
Firstly the background issue. I think the cabinet may detract from the focus on the subjects. I am a naturally nosy person so I started to look to see what kind of stuff you kept in there
. On the other hand that does keep the viewer interested but overall I think less "busy", so just suggesting the cabinet, as has been said already, may be the way to go, but that is just my opinion.
Secondly, I think by it's nature drawing with a pencil allows greater detail at a small size due to the fact the tool is small, pointy and so therefore can be worked tightly. I personally find it easier to control on a smaller size than larger, unless of course there is a lot of imagery contained within the drawing being executed, this then obviously allows for a larger scale.
And don't worry about being chatty asking questions. "Talking your toughts and ideas out aloud" so to speak, aids the learning process.
It's interesting to see the various processes you are going through to get to the finished product, so different from the way I work.
Phil
www.graphite-art.com