I used a shrinking urethane rubber system from Polytek Development on a 7 inch model and after 14 days the reduction is 50%. All of the detail is still there. I don't know if it is done shrinking yet. It is a fast setting product, so you have to work quickly. If this is done shrinking and it still isn't small enough for my liking, I can make a mold of this smaller model and pour more shrinking rubber in that and reduce it another %.