Just reviewed Sturgess sessions. Remembered one thing.
Initially, I thought the added latch on the following one being circularly rotatable, wondered how it works, and drove hundreds of miles there to see how it works (not only for this, of course). With it in hand, it's so disappointing -- this old modification is not imaginative at all, simply has a front end which can move inward and outward, the "latch" was just a flat spring, and it's very hard to operate.
http://jamesdjulia.com/item/2207-373/