What you have when stretching hides on forms is 2 opposing forces as the hide dries and that will thin the hide as It dries. Wire forms are really bad because the wire acts as a spring forcing against the hide. So getting the hides off the forms Is going to help you out on the grade.

Leaving most of the fat on the hide will be absorbed into the leather. After a few days off the forms that fat will be just about totally absorbed. That absorbed fat actually keeps the hide from drying out. And once In the boxes there's no air getting to those hides.

I'll try and get some before and after pictures.

I flesh as I skin and Use wooden stretchers. I hang them by the tail for skinning . After a few hours i give a quick scrape with a dull knife to get some grease out from under the saddle. another few hours later ill wipe each pelt down with paper towel to soak up the grease and then leave them until i have time to take them off the stretchers. Rat carcasses work well for any animal in my experience and are especially good when its male with full glands.

Not sure about that ND might just have something to say about that. And the Horicon Mash in WI produces lots of rats.

South Dakota 10 12 years ago had millions of rats.