Let the Plants Grow and have a good root-ball, a large root ball all the roots will stay in Tact, they'll literally slide right out, when your ready to Transplant wait till pots are on the dry-ish side (just before watering time) wont be any shock at all! (never transplant right after watering (heavy wet soil) and/or a "poorly formed root system/root ball".) Plastic is great for Transplanting out of...
Up-potting is Best Garden Practices, All seedling/young Plants starting out grow better in smaller amounts of soil forming a root ball quickly, its why many of us have 2 to 4 transplants before the final Pot! I go from Solo Cups to 1 or 2 gal (plastic) nursery pots then into 5 or 7 gal Fabric Pots.
inversely; If You start out in big pots seedlings/young plants will grow much slower. (not best practices)
I treat Auto Flowers (day-neutrals) the same way! they dont even know they've been moved.