Okay, here's some really great news.
So slick.
- iCatcher plays .m4b files without issue. So that's good news right there. Just tried it, works a treat.
- You don't need to use a cloud service to import media to it!
This is thanks to your use of an iMac. AirDrop is your friend. It transfers entirely over your local LAN, very likely at much higher speeds than over your Internet connection. Et voilà:
- On your Mac, select the .m4b file.
- Command-click. Select the Share menu. In the Share menu, select AirDrop.
- In the AirDrop dialog that comes up, point to your iPhone. You may need to unlock your phone.
- When the file is finished transferring, you iPhone will ask what app to open it in! Select iCatcher.
- iCatcher will ask you what "podcast" (folder) to add it to. You can choose an existing podcast or create a new one.
- Done. Now proceed in iCatcher to transfer the file to the Watch.
UPDATE: Yes, the .m4b file also plays on the Watch. The one I tried is 714 minutes long! It took a while to transfer from iPhone to Watch, but I just went about my business with the Watch on my wrist and the phone in my pocket, and poof, there it was.
I'm so happy with iCatcher that I've deleted Overcast, Castro and Downcast, none of which do all that I want, while iCatcher does ...with the exception, at this moment, of automatic transfer of desired podcasts to the Watch when new episodes are downloaded. (Soon.)
So once again to add a reality check, if you try the above but with a FOLDER of files, you will not get this happy effect. You can in fact find a place to store the folder that appears to be the iCatcher home folder (and is the same place that stores files/folders dragged into iCatcher via iTunes' File Sharing Window). But in both cases iCatcher appears to be oblivious that files can be added to its storage in this way.
So, like I said: IF your audiobooks consist of a single long file, iCatcher may be great. But if for whatever reason your audiobooks consist of lots of small files, 😢