Oh my goodness, I've never roasted pumpkins for the purpose of homemade puree... that sounds amazing... this recipe looks divine! (whiteonricecouple.com)
My issue with homemade puree is that the water content always varies and I don't like variation in baking. (texanerin.com)
Yes, you can use homemade puree, just be sure to drain it REALLY well before using it. (browneyedbaker.com)