Best Calibre Settings for Kobo Wifi?

I was just given an older Kobo Wifi (The one with the 'd-pad') and im wondering what the best settings are. Been reading/searching around a bit and its all quite confusing.

Tried a couple epubs and they work ok. The covers have white spaces on either side and there are larger spaces then id like between the lines of text. These spaces are not present when viewing in calibre or any other epub reader.

Any help would be great!

Thanks