I am interested in keeping as many rods as possible.
I would like some rods in return. If you are willing to accept a tinkerer with only a 50% chance, then a tinkerer with a better chance would still yield you more rods even you giving up two or three rods.
I am certain money is no object to you, nor is it to me, hence only charging 4,000 coins per rod. Therefore, the rods would be a much better deal than just charging for coin.