I've had this small set of horns in my freezer for a few years and finally decided to do something with it. The horn-a-long idea didn't come about till the generous Tradganger, Stiks-and-strings, that sent me the leather suggested I do one, so the initial mounting of the horns was not photographed. This is my first attempt at doing this so you'll have to excuse the amuteurishness of it.
The first stage was cutting the head down to a manageable skull size, skinning the fur off and boiling the skull to get the rest of the parts off. Then I mounted the skull plate on a piece of plywood that I figured would be the appropriate size with a mounting hole predone in the back.
I then filled any voids between the plywood and skull plate with cardboard and hot glue, trying to leave about a 1/4" gap between the skull and edge pf plywood to make room for a 1/4' layer of plaster of paris to make a relatively smooth and roundish object that the leather would cover nice.
Here's what that looks like.
Then I took a measurement of the distance between the horns, and transferred that to the leather and generally guessed on the cuts I had to make.
Then I stretched and stapled the leather all around the base as best as I could. The cuts in the back helped me get that looking halfway descent but I had to have a fold on each side in the front to get it to fit good. I debated about making two more cuts in the front to help with the wrapping but decided against it.
Then I got out the hot glue gun to get the back seams layed flat.