Hello @graphyss,
Thanks for being a PowerPress user and congratulations to reaching 300!!!
Podcast Channels is not a solution for your situation. Podcast Channels is really intended for additional formats, e.g. audio and a video podcast.
Categories can work, but for category podcasting to work with PowerPress you need to either always use just 1 category for each episode (the podcast category) or enable Strict category podcasting. It would take sometime to switch the category from one to another for 300 episodes.
Another option is to use Taxonomy podcasting. Let me give you a quick background first on taxonomies. Essentially category podcasting is a form of taxonomy podcasting specifically for blog post categories. Another taxonomy built into WordPress posts is called “tags”. For your example, I would recommend using the tags feature and adding a tag to your podcast episodes to tag them as your first 300. You could use the slug name “1-300-episodes” if you don’t have a better web friendly name for the tag, then just add that tag to the first 300 episodes, then enable taxonomy podcasting in PowerPress, add a taxonomy feed for the taxonomy “tags” and tag term “1-300-episodes” away you go!
The tag taxonomy works great for this in that you can plan ahead for the next 300 by always tagging the next 301+ episodes with “301-600-episodes”. You do not have to setup that taxonomy feed until you get to episode 601+. also what’s cool with this approach is you can keep your items per feed for your current podcast to a smaller moving forward. You could also tag your archive in other ways, such as by year.
Please let me know if you have questions or need more specific instructions how to setup.