pixelrush, smicha, p3toctane
I take it you mean adding custom resolution. There are a ton of menus for resolution in the regular application which would not be worth duplicating. Without any change to the script, you can just set up different render targets. Keep a couple for previewing using direct light and shadow normals (1 sample ppx comes out quick and clean for shading normals)and make others for your final output. Render targets appear in the menu in alphabetical order, so you can easily get to your favorites by the way you name them. Use preceding numbers such as in "01. Direct Light". There is no problem with spaces in the output file names (at least in Windows, hope that's the case with Linux and OS X as I have no way of testing those)
p3, Sorry about your FFmpeg. I hadn't thought about it earlier, but what you need to use is what they call a static build and place it in the root of Octane's script directory. I didn't use the shared library version as those force the executable to specific directories for different OS's making it difficult for scripts to find them. Also, FFmpeg requires that files are sequenced one after the other beginning at 1 to 4. As soon as there is a break in the sequence, FFmpeg stops processing images. That's why you'll find the option in the Animation tab called 'Force sequential numbering when using Step.' However, its still up to the user to make sure the sequence numbers begin at 000001.