IIRC Smuj the control systems on Albert were via hydraulic booster packs. Failure of both HYD systems wouldn't cause a loss of control per sé but the controls would become bloody heavy. Hence the foot rails on the coaming for both pilots to brace against.
I tried it in the Sim once but it was nigh on bloody impossible!
WRT diff power, we used to practice this on the ground for manoeuvring in the case of a loss of nosewheel steering (with diff reverse), I'm not sure how effective diff power would be in the air (Google Sioux City DC10).