I never quite understood the advantage of “touch back” as part of the policy, but your post makes it clearer.
They have to go back is clear, they have to be evaluated (have a hearing) is clear. If they are productive, how can they come back?
The answer is that there is not specified time before they can re apply. If the hearing decided they met the requirements for legal entry — no criminal activity, good record in school, good record on the job, no welfare fraud Etc. Then they could be brought back at once. The catch is that they must reset the time clock as far as when they can apply for any enhancement to their status. Like any legal entry there is a specified time for this.
Oh, and as to the hearing. My suggestion is to allow the immigrant to waive the hearing and go straight to the extreme vetting described above. If they do this, many can be handled without an overburden to our court system.
Note all this is after the wall and the deportation of people who have been involved in criminal activities.
Coming back ahead of those legally in line is unjust. We have enough injustice in this country.