I think there should be no more than six on a stage and there should be another six on another stage, and so on until all the candidates are particiopating. These debates should be done simultaneously with the same questions for each panel, and aired consectuvively over 3 nights.
After that first debate, those candidates who receive the most individual contributions whould continue to the next round, narrowing the field to six.
It seems fair to give them all one chance to be heard by the public. Their performance and voter response in contributions will then determine their inclusion or exclusion in the rest of the debate series.
The public can read their positions and send money to the best candidates. That's what I do and it is not difficult. I have no use for a soundbite festival with post-spin all run by the enemies of America and capitalism. If the "public" is too stupid to do that, then they should not be fed these "debates" by liberal media. It serves no useful purpose.