I've never heard of Musher's Secret until this thread. I do know, I applied Bag Balm to Syd's pads after I discovered they burned off when she came back in after the evening "potty". I felt like a real shitheel. I was thankful I had a tin for my cracked hands. She only tried to lick it off once and apparently didn't enjoy the taste (she recoiled adamantly--it was almost amusing).
Her pads returned to normal relatively quickly and I continued to use it for protection. While the pads were healing, she got a "good" slather before I let her out then a cleaning with a paper towel when she came back in. It seemed to absorb easily and there was never any evidence of carpet staining. I sure as hell would have heard about it. After a couple weeks, her pads seemed to toughen but were supple. We'd just do a bit and rub it in. By the end of winter her pads and my hands seemed to acclimate and no longer an issue.
If she hunted, she'd be pissed at River for a bit but damn well learn to walk with the boots.