I'm sorry you haven't had success so far. Your snake is your pet, and the decision to force/assist feed is a personal one. Only you can decide if you want to go that route. Whether you decide yay or nay, you can continue to try different scenting tricks from time to time.
By the way, have you tried taking the snake for a ride? Sometimes shipping a nonfeeder turns it into a feeder. Maybe it's the jouncing, maybe it's the relocation. Whatever, some have had similar success with putting their snakes into a container, riding it around for a while and/or setting it up in a new viv/new location.
Good luck, whatever you choose.