Not a weighted blanket, but what i use is an empty king size flannel duvet, folded in half, as my top sheet (in winter, anyway!). So that is four layers and very long. Next i have a twin size poly-filled comforter in a cotton duvet. Then on top of that, i have another king size cotton duvet, my fancy one that matches the pillowcases, which is empty unless we are having a very cold winter.

I used this setup for the first time last night, and it was amazing. Very cozy and heavy. I used to have a smaller older rougher flannel duvet - not as nice!