Everything in life is a tradeoff.
The mount allowing the Lyman 48 and the scope to be present simultaneously seems to place the scope too high for quick instinctive shooting and probably gives little or no "check weld". The typical Griffin & Howe mount places the scope lower, sometimes much lower, and avoids these drawbacks. It's all a question of shooting style. European style shooters would have no problem with the high scope.
True the Lyman 48 slide can get lost in a typical G & H setup, but not if it's is placed in the trap butt plate, as it should be, when not mounted. G & H sporters of any vintage often still have them stored there.
