Add more sawdust boxes with better scoops and keep the sawdust boxes filled. Every place only had one sawdust box this year and it was often not near half the toilets it was serving and the cups were bad at scooping enough.
Get a proper pre-festival communication on how there will be much less seen and smelled when sawdust is used and that you are doing your bit etc. and people will actually do the sawdust bit. This year they just mentioned they'd be compost toilets and linked to the providers site way way down in a general info mail.
Have a little brush to clean up spilled sawdust as any sign of "mess", no matter how benign, on the seat area looks off putting.