A variable diopter is a very old lens design. Modern lenses are designed differently and do not need such an optical design due to cost and avoidance of additional glass elements. This is a logical and correct solution to the dual focus nature of the simple anamorphic system. I want two.
The rangefinder does flare easily. This requires a box. With the focus gear up front how would focusing be accomplished mechanically ? I suspect a follow focus device is required. Andrew, have you tried it with a matte box ? What issues do you see ?