Stith also made a 2 piece W&E adjustable top mount. Rear mount had built in W&E adj. "peep" sight. Very solid and QD. Shown here on 721 300 H&H with a BalVar 5 (2.5-5x). The rear mt on some used the factory receiver sight holes, others the holes on top of rear ring.

[Linked Image from i.imgur.com]