Hey ddingatlanta now you've done and got me all excited about seed balls some more. Make sure to get an early start on them, because they are much more weather resistant and can take longer to germinate than just a plain seed would.
Yes, I turn by hand. Which I do, not only because I'm cheap. If you've ever made ceramics, it's a lot like throwing clay on a wheel, the more control one can have over the wheels movements the more precision can be used. With a motorized system you are most likely not going to get that level of sensitivity. Also, the only carbon emmisions I emmit is from my breathing. It takes me 2.5 hours or less from start to finish to do a full batch. It's really enjoyable, and most of that time is spent adding ingredients and analyzing the seed balls progression. The bucket keeps excellent momentum on its wheels and isn't a back breaker by any means.
I have two get done fast tips:
1. Don't try making a full batch for your first time. You might run out of room in your bucket by the time you've added everything and then it can get stresssful trying to split the batch.
2. Slowly moisten the mixture. If you can, avoid making the media too sticky/moist so the seed balls won't form a conglomerate with each other. It's going to save you time if you don't have to break these conglomerates into smaller seed balls again.
Best wishes in your endeavours