Of course you can teach a western horse to ride english.
Since most western saddles are heavier than most English saddles, a horse could probably run faster with an English saddle, specifically a racing saddle. However, if the rider's weight combined with the saddle is more than the western saddle and the rider's weight then the horse could run faster with the lesser weight.
Saddle seat is a type of English riding that involves a high-stepping horse, and the rider has his/her legs farther out in front than in most English saddles. Western is a type of riding where the saddle has a horn, and is deeper and more secure than an English saddle. Western riders do not jump.
your not sopose to. but yes if it is a thin smaller saddle pad you may. you can NOT! i repeat NOT! aloud to use a English pad for a western saddle as this pad may be too small for the saddle and with bridged the withers and back of the horse. be carefull on what you use on your horse! i reqamend to buy a western saddle pad if you are planing to ride western.
Clydes are rather big horses. It's not the type of saddle that's important, but that it fits. If it does, go ahead.
If by classic, you mean english, yes. what is most important is the horse's comfort
It all depends on the horse, and how he's been trained. Some QH's are better with the English saddle, others better with the Western saddle. Most QH's are trained to accept the Western saddle, though many other horses have been trained to accept both or either or. So it ultimately depends on both the horse, the rider and the trainer.
You can use a western saddle on any breed of horse or pony providing they have been trained in western riding.
You can but its not recommended. An English saddle is much lighter and is easier on the horse... but its OK, just for low jumps.
You can ride a horse MANY different ways. There is English, Western, Bare-back, Side saddle and many others.
I would do a close contact saddle or for western, a tree less saddle
In the horse world, you can have many types of saddles, but the two basic saddles are English and western. There is a cross between the two of them, but not as much people ride in them. The western saddle is much bigger and heavier than the English one, and has a horn. The cross is shaped as a western saddle, but does not have a horn.