The mixing positions on the plan are all the possible places to put the desk. Mix one is unfortunately the normal position for a standard seating arrangement as there is limited room elsewhere. You are slightly in the ‘wet-workshop’, but you are at floor level.
Mix 2 is the preferred position for most standing gigs.
If you only have a small desk i.e. an LS9 Mix 3 is possible though you will be rather squashed!
Mix 4 is ideal for theatre events though rarely gets used for live music as you are very high up in the control room in a box!