The barrel grades on L.C. Smith were no different than any other gun manufactures, you got what you paid, the higher the grade the better the barrels and workmanship.
In catalogs for Hunter Arms, extra barrels were half the price of the gun if that is what you wanted. You could also order a cheaper barrel or a more expensive barrel.
An example would be in a Deluxe Grade, in 1913 this gun cost $1,000, an extra set of barrels for it would be $500. They would be Whitworth barrels from England.
As to strength of the cheaper barrels, all L.C. Smiths were tested with double loads, and in the 1920's when they started stamping the barrels water table or what ever you want to call it, it had NP along with HAC incorporated in the logo.
As to what is better, how many Field Grades are there still in use?
