Somehow I do not think RTV and a griddle will workout too good. I havent poured that mold in awhile now but if I remember correctly the biggest help to me was getting the plastic temp right. Too hot causes lots of over pour while too cold gets cold cracks, I use to start at the body first and fill it up, then do the detailed leg work when the plastic cooled off so that you can pull the plastic where u wanted it rather than pour it.