Sometimes you just have to make do with whatever is in the tack room. I have ordered a queen for my new saddle, but it hasn't arrived yet and I wanted to take it out for a hack. Fighting the saddle for correct position certainly didn't appeal to me and there wasn't any vet wrap to hand, so in a flash of inspiration I took one of Owen's fetlock boots and fastened it around the upright horn.
Worked a treat! Had a nice longish ride, including some good cross country trail work.