Yes, short course in strain gauge 1 I can't believe they work at all
2 they are superglued to the steel shaft and sense the stress of the steel as strain (torque) is applied by stretching or contracting with the surface of the steel
and if I remember correctly, the change in resistance is .7 ohm max, it may have been .7 miliohms, I'm checking.
Anyway, you think it is the high gain that is making things oscillate, why is it stable until I connect loads to the FETs?
Thanks
Kinarfi