Jaco:

Since you're having this rifle built, why not use a quarter rib that is long enough to get the rear V well away from the eye. That should help some with the presbyopia. In conjuction with this, stay away from short barrels - stick with 24" at least. Quarter ribs on bolt rifles are almost always too short.

The sloshing of mercury reducers drives me nuts. At 10 to 11lbs, a .416 should be fine without one.
---------------------------------------------------------------------------