I believe it is important to get those outer frames built out, so move the outer frames in and combs that have started being drawn to the outside. As soon as that happens, take a frame of brood from the center of the bottom box and move it up and replace the hole with a frame of foundation. Congratulations on doing it right and having a booming colony so far! Just don't let them get too crowded. If you have been told you will get no surplus this year, ignore that and have a super ready in case your bees need it!