There is a pop up window <shift>6 I think it is, that will enable you to "select" 1,2,3, or 4 engines at a time. It's totally unique and brilliant. What that means is that you can select all 4 engines, I think this is default anyway, and set power to a given level, then select say engine 1 and increase the power of that engine alone to aid turning right in taxiing. This is just an example though.
So yeah, you can use this bird with a single throttle. I use an X52 Pro, and that only has a single throttle. A2A think of everything
Oh p.s. this works for the mixture too by the way