I like video ref as it is. The 3 call rule should apply to talking to the ref about a decision in general play.

Can the video ref just radio down to the referee anyway to advise on calls, with the ref asking him to look at it?
In the event of a possible knock on, we see 4 replays by the time both teams have formed a scrum, is the video ref not able to just radio down in that time and say the ball had actually been stripped or something?

Or 1 challenge In each half for each team, has to be a penalty if the call is adjudged to stand, if the call in American football fails then the team is charged a timeout. Also every scoring play in AF is reviewed by the officials, would that not be better instead of the video ref being used to only check certain scoring chances.

Any challenges by the captain should not stop the ref's/TJ's calls.

I guess that a lot of calls will be about forward passes. I am still keen that any suspected forward passes leading to tries should be tested by the video ref. But first make sure that the ref's/TJ's (and particularly the commentators) understand the rule relating to momentum of the ball - all passes must leave players hand in a back/flat direction!

I know there are arguments about camera angles misleading players, officials and spectators but at least the video can help to give some guidance.

IMO the whole video ref thing is a joke.
It takes a high speed collision sport and literally micromanages it.
Let the match officials make the calls. Yes they will make mistakes, just like players, coaches and fans.
It's an uneven playing field in this country because all the games are not covered to broadcast standard and certain teams get more coverage than others (whether it is an advantage or disadvantage is open to interpretation )
I just hate watching a fast flowing open game coming down to a microsecond of blurred video after 2 minutes of indecision. That is not sport!