I agree that he is not worth double, simply because he is not twice the player DSaf is. However, as Jaybro says, we need to throw more money at the players we need, including because of location and the club's lack of recent success. IMO, it's a question of how much he is worth to us, rather than how much he is worth on the market generally.
It's a perfect storm for TPJ isn't it? He's off contract at a time when the number of quality props is low, and the number and quality of offers is very high. He seems like a smart guy, which is surprising that he makes it so open that he doesn't intend to move away from Brisbane. If he doesn't sign with us, our public interest in TPJ is a notice to other props that we have the money if they are interested. Will be interesting to see how it all plays out.