DB - two points - firstly I don't think a 6 monthly requirement for UA/UPs is good enough, monthly would be much better. Secondly - pilots should practice them in the real aircraft because, no matter how good your sim, it can't accurately replicate all the 'seat of the pants' proprioceptive feedback from the real machine.
I don't think there is any difference in a UP recovery between in a light single and a heavy twin.
Are there set parameters for the 6 monthly sim UPs?