i always thought it was double the weight.
The general rule of thumb has always been 1.5 times the loaded weight of the rig as a minimum. Nothing wrong with using 2X though. Many guys will double (or more) the loaded weight to get more pull when the sticktion rate is really high. Sticktion is defined as how stuck you are, i.e. what is holding you there. For example; a high centered recovery will not take near as much pull rating as being mired over the frame and laying on the the floorboards with all four tires spinning helplessly in sticky wet nasty clay. The rating for 1.5-2 times the loaded weight is to account for the force of the rock, mud, gravity or the combined things keeping your truck from having fun. You may need max pull rating for only am inch or you might have to do multiple long pulls at max rating. So having the right tool at hand for any job is very nice.
My opinion, for a Raptor, go for a 12K rated winch that will fit. You may need it for self recovery or to recover someone else. Winches are one area (within reason) that bigger can be better.
Using things like math and geometry along with extra equipment can get "more than rated pull", but that is beyond this thread.
Winches can be dangerous, please get educated on using them safely BEFORE you need to use it. Sorry, I had to add that because of what I have seen in the past. You all are adults....carry on.
