The reason that the large bore instruments seem easier is the feedback to the player that the artisan designed into them. That is much easier on a "pro" horn not primarily designed for durability........ The more advanced designed can be more efficient without "strangling" the player. I have often posted that a pro horn is NOT a good beginners or intermediate horn. The feedback possible requires good breath support and embouchure. When the brain gets involved in the servo system, the pro horn simply has great advantages.