Well the 90% is arbitrary, it can very well be 89.75% too, that is not the point. We should find a number that ensures both social flexibility and evolution of humanity, and also as much sovereignty to the individual as possible. So I believe the number 90% is good for this. Maybe 75%, but I would personally not go lower than that.

Switzerland has already been debunked, it's not DD. You need to collect signatures and they have all sorts of checks and balances. It's still a representative democracy, and you can only have referendum on certain topics, so the questions are controlled, it's an Overton Window, it's just that it's less opressive than other countries. It's still not a free country.