So after some experimenting I think I found the perfect setup for those of you who have two throttle levers, see below :
The knobs are all saitek (they came with the second lever). I just cut in half the big knob myself, as you can tell from the excellent craftsmanship. In order to get the flap lever to work, I use, as discussed above, this excellent script. The spoiler lever works "out of the box" (first time I see that in xplane).
The big knobs are for engine 1 and 2, and the small ones for the reversers. In order to still get full power when pushed all the way forward (or all the way back for the reversers), I just recalibrated the axis in X-Plane. Works very very nicely.
Jonathan