The surface of the package you linked to is "F", glossy. "N" would be matt, the other two surfaces mentioned in the data sheet quoted by Rudeofus are less common.
Not sure what you mean by "framing", I have a small, dedicated easel for this paper size (my larger easels will also handle this paper size, but I find it a bit clumsy to use for such small sheets) and set the margin to 5mm. Of course you will have to crop the long side when doing this. When I want to fit in the whole frame (avoid cropping) I still set the easel to a 5mm margin, so as a consequence the bottom long sides gets a broader margin, which can be trimmed later or just left as it is.
As Rudeofus mentioned, it's not to difficult to cut your own smaller sheets with a bit of practice, for example I cut down 12x16 sheets from a roll, which I cut down further to 8x12. The ratio changes from 3:4 to 2:3, which coincidentally is perfect to fit a full 35mm (or MF 6x9cm) frame.