Pretty sure the firmware won't let the satellite shifter shift the front derailleur, though I haven't tried it.
It will work, the Fitting instructions even suggests it as an option, but it does state due to the angle of the buttons it wont be as ergonomic as it should be, ideally they'd made a LH specific shape.
RE. The size, they do look pretty chunky, but once your riding they blend into the bars quite well and I would say the size is just about right for operation. I 100% need them under the srm bracket though, had a couple of accidental shifts when switching modes on the headunit and 1 shift with my knee while out the saddle. (if that technique could be controlled they could be used as great sprint shifters too