After day 1, we are doing great. 3 concurrent threads of work was going on in the room. We were getting the database ready, regression testing the code, and migrating data. Remember, J-RAT's entry criteria is that System Testing is done. So we need to make sure the code is regression tested completely before starting.
At the end of day-1, we know that we are one day away from actually start the process, but everybody is buying into this approach (most people in the room is new to this intensive testing mode).