How to go about recording a time-lapse video in OBS for youtube (settings to save the most space or program recommendations)?

Can anyone offer any guidance on what settings to use to record a time-lapse of a digital painting in OBS to help save space? The video will be uploaded to Youtube! This will be my first time recording one.

I know I can speed up the video files in another program but I'm unsure about how to utilize the settings (canvas resolution as well) to save the most space. Most of my digital paintings can take 2 weeks to complete at about 2-4 hours a day working on it.

Thank you!