I also have a 2007 GC2310 (1100 hrs+/-). Key on mine is turn LEFT (against spring) to activate glow plugs; turning right is as expected, first position is power on, second spring-loaded position is to engage starter.
My only suggestion would be to activate glow plugs longer when it's cold -- I'll turn key left (GP), hold for 30-40 seconds, release for 10-15 seconds, then turn left again for 30-40 seconds.... then turn right to power on & start.
Seems like I've also heard that "sneeze" sound occasionally, never paid any attention to or worried about it. Figured it was just the result of an "almost fire" in one of the cylinders.