As to idle speed adjustment, I backed out the left throttle plate stop screw a turn or so. No change. Applying "slight" counter-clockwise (anti-clockwise) torque to the cable attachment "spindle" atop the left throttle body slowed the idle. Thus, I went to the other side. That screw is not as out-in-the-open as the left side, but it is doable. However, it was rather tight from not being moved for 15 years as well as the electrolytic activity between the steel screw and alloy throttle body.
The Eklind 2.5mm ball-end wrench was a so-so fit, slightly on the loose side to suit me. Scanning my eclectic assortment of otherwise useless sockets and bits, I spied a WIHA T10 hex bit. Torx bits have essentially the same contact surface as a standard hex wrench, so why not give it a try. Aha! And, using it with a Pittsburgh (Harbor Freight) right angle ratcheting screwdriver (an exorbitant $2.99) did the trick. Idle now being too low, I brought it up to 1050 +/- using the left throttle body screw. All is right with the world once again**
**A few notable exceptions, but all-in-all rather good.
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