Horns were put on saddles when roping developed in Mexico as a way to handle cattle on the open range. Prior to that the lance was the Cowboy’s Friend. 
I once rode a three your trail ride on a Walker in Stubben Tristan. Never again. After cycling through bunch of alternatives I settled on the Stubben Scout. Virtually identical in seat to the Stubben Siegfried, but with longer bars and 10 d-rings. My wife rides a Siegfried VSD-DL (dressage length flaps) and likes it a great deal.
If you want real light weight and security look at a McClellan. It served the Army, in a half dozen different versions, from 1859-1948. I don’t find the Mac comfortable but you might. I prefer the Grimsley Dragoon saddle (predecessor of the Mac) or the Whitman Officer’s Saddle (that in 1887 almost replaced it). All of these saddles can be had in reproduction form from custom makers for under $1000.
The Army’s last official saddle, the Phillips Officer’s Saddle of 1936, can be found but are getting rare. Again, I don’t like the fit for me but you might find it OK.
I’m not a fan of Aussies. They just don’t work for me.
Steele makes an excellent line of Plantation Saddles. A couple of folks I know ride Buena Vista’s and swear by them. The Trooper saddle is the modern evolution of the British Universal Pattern cavalry saddle; it first saw service in 1795. Tucker, and somd others, make good quality versions of this type.
The traditional western saddle, built for roping, will be strong and secure but will also be heavy so as to stand the stress of 1000 pounds of cow at the end of a 35’ rope. They will also not give a lot of “close contact” feeling. Some saddles do follow this shape but are much more lightly built. I’m not so sure about them. You might find them OK.
There are a lot of choices, here. Shop around and try out as many as you can.
Good luck in your search.
G.
