defensive systems for the number of refs on the field. However, I don’t think there should be more on the field, I think they should add 2-3 refs in the booth.

They could work with the refs on the field ceding primary control to the field refs, but each of the refs would have an assigned area of the field to monitor. They then could call the penalty down or take enough time for 1 video replay on plays that were obvious to determine a penalty.

Then you get into the review process where the booth guys review every play in say 10-15 seconds. Not a lot of time, but just enough to see if there is anything conclusive with no interference of the game. Somewhat similar to what is supposed to happen now, but more selective, meaning that the video evidence has to solid.

If they find what may be conclusive evidence they may buzz down for an official review to stop game action for no more than 30 seconds of review. If it’s not obvious after 30 seconds, move on, play stands.

Coaches could challenge plays at any point in the game so long as they have a timeout remaining. And since they are a third party calling for review, they will be given more time for the review, to allow for the potential of a borderline call to be examined and overturned, say 45 seconds to 1minute for the review.

Rough draft of my opinion.