From my personal experiences when it comes to plastic memory...some brands are much worse than others. The best plastic I have found that has the least memory issue is Ozark and what ever Don Iovino is using. About ten years ago I did a comparison (posted here on T.U.) of 6 plastisol manufactures. That test consisted of raw plastic settling, clarity, shore, water absorption, memory, Max temp before scorching, viscosity verses temp, buoyancy and strength. All tests were done being as controlled as possible, using Tentalometers, Durometers and optical sensors. I will look and see if I still have the white papers, pie charts and graphs......that info is on one of my old computers some where.