Just tried the G.50 today to see how the Breda guns do (another subject this one, but the guns on this bird rock), followed by some flying around in a Blenheim.
It seems that the air-cooled radials are very temperamental and highly susceptible to temperature changes (which is actually realistic).
For example, i broke the oil gaskets on the blenheim by enabling extra boost and adding some power (RPM first and throttle second) over the initial limits.
In the G.50, i throttled down to descend for landing, lowered gear and flaps and by the time i was in landing configuration and had to apply power to overcome the extra drag the engine started cutting out, running rough and producing inadequate power. I had something similar happen briefly during the sortie and i cured it by throttling up and closing the cowl flaps and oil cooler a notch or two (in a similar fashion, i had to apply some carb-heat to keep the blenheim running smooth at 8000ft).
It seems that while i was throttled down and watching the levers move in the cockpit while lowering gear and flaps, my engine was either shock-cooled or my spark plugs got fouled. In any case, i didn't have enough airspeed or altitude to recover properly and i made a hard landing about 700m from the runway threshold, clipping my right wing and one of the propeller blades.
For now it's quite fun to mess with things and try to discover how stuff works on my own, but i agree that some form of expanded documentation would be needed in the long run, perhaps as part of a future patch in the form of PDF files.