I use a 7' x 4' drum that turns at approx 20rpm. 8"x 3/4" paddles. I don't know what kind of hide you are softening, but here is an example of what I would do for a black bear after tanning, shaving and degreesing.
1. oil, I use Satinol and mix 50/50 oil and water. Heating the oil and water helps it penetrate better.
2. after oiling roll hide skin to skin and let sweat over night or at least 8 hours.
3. open hide and give second light oil. I will scrape the hide with a paint scraper at this time to help break the fibers and let the oil penetrate better.
4. hang or stretch hide and let dry to approx 75% dry. A fully dried hide will not break as easy.
5. drum in 200# of corn grit or sawdust median with 1/2 gallon of mineral spirits mixed in to help clean and degrease.
6. drum for approx 2 hours then pull hide out and let it finish dry for another day. Drum again for approx 2 to 4 hours depending on hide thickness.
5. screen for approx. another 4 hours to finish breaking and remove corn grit or sawdust.
I like to run 3-6 bears at a time to help with the breaking process. The more hides the better.
Now here is the real kicker...I am learning it is a lot easier to send the hide to a reputable tannery than continue to break my back

Anyone in AK want to by a drum?