best way to mold in bumpers....

okay guy. I know I will get a lot of different people saying not to attempt to mold in the bumpers plastic to metal. but I am going to do it anyway, I know eventualy it will crack and need repair. but thats something I am willing to deal with. what I want to know is, what is the best way to perform this. My thought is that I will put a thin layer of fiberglass over the seam, then put another larger layer over that which will blend in tot he bumper better. then I would use a skim coat of body filler over than and sand it all down really smooth. Then I will stack up a bunch of fiberglass layers along the back for the primary support. How will this work you think guys? My thought is that it should hold up pretty well, but I am no full time body repair man or custom guy. Any help would be great. Thanks.