I have a horsewear one (i think it is anyway... it comes in blue stripes too?).. looks like a new market blanket, but is fleece and wrap around, love it, doesn't slip, is cosy and doesn't let light showers through.
Not sure about sizing though, sorry
The mark todd wrap around hi viz sheet is pretty good - I would get another one if anything happened to mine.
I also have a plain fleece mark todd wrap around exercise sheet - love both of them.
In theory you take two foot of the normal sized rug for the size of an exercise sheet. It doesnt always work, but its a start!!
I never wear the wraparounds over my legs, I put it under that saddle flap, over the girth straps.
I have a lovely light weatherbeeta fleece one, a hi viz waterproof one and a thick thermatex one! My boys feels the cold in the winter!