Ever try to figure out how to get the Hobbs meter to work right? If you wire it to the master, eventually you forget to turn the master off, and come back next week to a dead battery, and many bogus hours on the Hobbs. Here's how I did it: use a Radio Shack microswitch, make up a thin steel bracket that you can slip under the clamp for your front carb, attach the switch to it, bend the lever arm on the switch until it just contacts the end of the oil pump arm, and the oil pump lever lets the Hobbs start ticking when the engine comes off idle. (Hard to see, ain't it? It's that little black thing just above the end of the oil cable barrel)

Although it seems to work trouble free, I was not happy with the flexibility in the MKIII aileron hinge. The whole assembly could be made to move at the tip due to hinge bend. My cure is to use some stainless L hinges identical to the ones that secure the front edge of the horizontal stab, and attach them to the outboard end of the aileron, and the rear spar. The hinge pivot distance is identical to the piano hinges. Use an AN-3 bolt with locknut for the pivot. After the aileron hinges are on, position the stainless L hinges temporarily using hose clamps, pivot and adjust until everything is smooth and aligned, then mark the holes, use 3/16" stainless rivits. It's RIGID! But I still ended up installing the aileron counterweights: the extra weight of the adjustable aileron trimtab on the right aileron made it buzz at speeds over 85 mph.