Yes the Gripping Beast riders have a wide seat, as you put it

.Thats part of the problem I have with the horses they come with.They are skinny for the riders,at least most of the riders.Plus there are only 3 poses and some of the details are either soft or badly cast, I cant really tell which.
Funnily enough I like the way they fit on the GW LOTR horses I have, just don't have enough of them.
So my next question would be, are the Perry horses you bought as wide as the Rohirrim horses?
Thanks, Pete