I think 4 per category is best and then run the polls in Threads would be the cleanest and easiest way for it to be done. Also, this would promote the Community Threads sections as well. Many people have their votes tied up and with limited VP, it's not the best option to expect people to use them in this way. You could do weekly run offs as well, but that's not really necessary if you trust your curators to be good judges of what's quality and genuine.