Very useful post. I have been experimenting with finishing different processes to try and really understand "what does what". Right now I am working on straps that I want to be pliable, and really feel natural and wonderful. I've decided to try neats foot, sunshine, then add some color once I know what the oiled color looks like, then seal with some kind of beeswax compound.
I first tried applying the neats foot with a wool dauber and it came out too blotchy. I couldn't control it very well. I switched to a piece of old T shirt, which I would put some neats foot on, then work it in with my hands, then apply to the strap. Much better. I hadn't thought about flannel, but suspect that will be even better to work with. I am letting them soak for a day (may give the blotchy ones a week).
I was originally planning a 50/50 beeswax/neats foot combination as a finish, but now suspect it will be a bit too oily.
Thanks again for sharing your experience, I am happy to do the same.