Riding Lawn Mowers

I want to buy a riding lawn mower for residential use. my yard is approx 1 1/3 acres and flat. I am considering the following models: YTA 18542--18.5 hp,and the YTH22V46--22 hp(hydrostatic),and the YTA22V46---22hp.My yard has two gates that I have to clear with the mower. one gate is 45 inches wide,and one gate is 50 inches wide. question one: which mower of these models is best suited for my yard? why? question two: what is the width of each model identified and will they clear the gates ,as dimensioned above? question three: does each model have a grass blower? if so ,is it easily removable? and, if removed, would the width be reduced? and, by how many inches? question four: what does hydrostatic mean? your answers are greatly appreciated.please try to respond quickly,as I must make the purchase soon. thx.