Thanks for the name of the glaze. I don't have any of the Gare glazes. Going to check some of those out. I particularly like the glazes that mimic the high fire glaze look and this one has that quality.
I like your base because it's simple and organic looking. I too am new at figuring out bases for my busts and I came up with the same idea as you for my Noelle base. :-)
With the nose of your horse sticking out, it needs more base at least in that direction. You could make a wooden square at the bottom that the clay attaches too. Or the next time, make a beveled edge on the clay at the bottom which makes a larger footprint.
I'm going to experiment with taking some left over granite slab and chipping up the edge randomly and making bases with that.
Maybe someone else will have more suggestions for ya. I need em' too.