For the ANTminer U1 optimization, I can only speak for the Windows version (I'm running Windows 7 32bit so BFGminer 32bit for me).
I run the following:
bfgminer -S antminer:all -S erupter:all -S all --set-device antminer:clock=x0981 --icarus-options 115200:2:2 --icarus-timing 2.5=90
I have seen another user further back in this forum run the following:
bfgminer -S antminer:all -S erupter:all -S all --set-device antminer:clock=x0981 --icarus-options 115200:2:2 --icarus-timing 2.5=90 --weighed-stats
I stopped using the icarus settings shown here. It throws off bfgminer's tracking of the average hash rates, plus I found that it reduced my actual work done by about 5%.