OK. Use GUI version. Enabling
Stretch should remove margins almost completly but it will also disturb image ratio. IMHO enabling
Upscaling is better. If you planning to use zoom experiment with HQ (It is little buggy now. I would wait for new KCC version.) or Ultra mode (It create very big files.).
As input use CBZ/CBR/CB7 file with
ComicRack metadata.
Use
proper file structure inside input file - In this case TOC will be generated automatically.
And upload it with Calibre to get HQ cover.