I tried the 50/50 Milliput and Plasticine today, For the sake of experimenting, I weighed out 12 grams of milliput and the exact same of white plasticine. Rolled it out like i normally do and checked it this morning. The results are exactly the same as when i use 100% milliput. I thought it would be a bit plyable like fimo when when rolled thin but it wasn't. For context, I have added some pictures of the results and a picture of how I used it, I dont use any rollers so I cant comment on that side of it, but for my "concrete" 40k bases I cant see any difference.