Blender: Grid Snap Settings(?)

[StR404]

I've got the basics of Blender down, and I know the controls fairly well (At least the basics for creating an object.)

I understand that 10 Blender units are equal to 1 Oblivion unit, at least by default, and I'd like to set it up so that Blender will snap to the Oblivion size so I can save it as default. Incidentally, I'd also like to know if you can have less than 1 Oblivion unit on an object without messing up the object i.e. A rod that is .5 Oblivion units in diameter. lol, almost said radius.

 

I ask because I'd like to make a full-size replica of a sword - That has yet to be made, but has been extensively designed - and converting multiple times will inevitably lead to me messing up a decimal or digit at some point.