I've used this tool from the developer's instance. It works as intended. I haven't tried the new release.
I was skeptical that it would work to be honest. Particularly as I am a kbin user modding a kbin community. However, I was able to create an alt account on a lemmy instance and give the account mod status in the kbin community. So I use that account to post. I would be nice if kbin could be directly supported but I understand there are ongoing issues with the kbin API --- lack-thereof. For time being, the workaround has been functional.
Logging in to the interface now, I can't see any of the previous scheduled posts I've made which did used to be visible. Maybe the new version is a breaking change from prior. Which is fine with me. This kind of thing will obviously have an experimental nature to it. I am hoping that going forward the previously-scheduled posts will be visible because it is convenient.
My review is five stars ⭐⭐⭐⭐⭐ for the application. Thank you @rikudou for building and sharing this very useful application.