This is exciting! Lots of interesting experimentation here. 
Really cool that voters get to decide on the OP distribution between different categories after the application deadline when we know how many have applied and maybe have a general sense of the quality of applications. Maybe some useful data can be gained from the review process?
I’m curious - did you consider asking voters which category/categories they would be most keen to vote on? And if you did, what was the thought process behind choosing the random sampling approach here?
Also - I look forward to see what kind of interaction there will be between citizens and guest voters and between experts and non-experts! Aside from the question of whether some people are better equipped to vote because of their past experiences (which I would expect to be the case), I would hypothesize that introducing experts into the process could raise the level of all voters …but only if the conditions are conducive, and if experts and non-experts alike are willing to enter into fruitful exchange. 