I reackon it's Dykes. It's no secret that the Waratahs are looking for a 5/8 after having missed out on Johns. I reakon he'd do well at rugby, he's got a reasonable kicking game, won't need to do too much tackling and there's a bit more space.
I doubt it's a forward given the transition is a bit more difficult than for a back. I mean lets be serious here, a modern rugby league forward is nothing more than an oversized back. Also, there isn't a real good history of forwards switching codes. I know people will jump in and mention Ray Price and Brad Thorn, but how long did it take Thorn to come good? I was arguable one of the premier forwards in league when he left.