I wound up putting a weaker spring on my 28/2. It would only control to about 5 cycles with the stock spring. I had to run the adjustment nut way down to finally get it to control to within 1 cycle with the weaker spring. I messed with different lengths and found that with the adjustment nut at the original location on the screw (about 3/4" to 1" from the end) it still wouldn't control very well even with the weaker spring. Might have something to do with the guts of the governor. With the weaker spring the adjustment nut is screwed down much further ( the outboard end of the screw is almost flush with the inboard edge of the flywheel) and it controls great. Again it may have something to do with the guts of the governor. The stock spring may keep it at just the wrong point where the governor has a hard time breaking over "hump". With the weaker spring and the adjustment screwed way in, it seems not to encounter the hump. It may have some machineing issues but changing the adjustment has helped mine tremendously. I can load more than 42 amps then unload and it controls just right for me. I can email a pic if you want and can send you a spring if you want, no cost. The engine doesn't strain with the load I have put on it so far.
Glad you have your engine running and producing already. This is my first Listeroid and so far I have been well pleased with it. I'm almost finished with the shed for it then I can concentrate on the final connections such as hooking to my manual transfer switch, larger and remote fuel tank, closed loop cooling. I picked up a heat exchanger for an air handler that uses hot water to heat a home. It has a Grundfos circulation pump on it already. I don't really care for the twin water outlets' location on the engine but not much can be done there. I intend, read hope there is enough room, to put a thermostat in each head before I finish the cooling loop.