Changing soil?

I would not. My thought is you do not want to do any transplanting or anything that can shock or stun the plant. It is on a fixed schedule and will ripen and finish based on the calendar. So, a week or two recovering from a soil change means a smaller plant and smaller yield. I would do the best you can with the soil you have. Plants are tough and can work with some really dense soil. It may take a little more time for your watering to soak in but be patient and water slowly.