Problems converting Nook HD

I'm trying to convert a graphic novel to work on my Nook HD, but there doesn't seem to be a setting for it. There is the HD+ setting, but that turns out too big (doesn't fit the screen)

I can't find any setting for the resolution of the regular Nook HD 7" (1440x900). Is there a way to input custom resolutions? Or am I just missing something...

Thanks.