Staking--composition of electors


#1

In the cardano docs it says
’Slot leaders are elected from the group of all stakeholders. Please note that not all stakeholders participate in this election, but only ones who have enough stake (for example, 2% of the total stake). This group of stakeholders are known as “electors”.’

I realise this is just an example, but taking stakeholders with at least 2% stake seems unsatisfactory as the number such stakeholders is not known, and could be 0. Wouldn’t it make more sense to take instead the top x number of stakeholders? My questions are

  1. What is the target size of the group of electors?
  2. Is there no randomisation in the selection of the electors? For example, will the top stakeholder be an elector in every epoch?