Sandro and Bernard have taught us a valuable lesson on free transfers. It's not smart business if you pay them way above their value to secure the deal, as they'll never be moved on afterward.
Should maybe think of increasing the signing in fee in turn for reducing wages. Only down side of that is if you do that and they play well they will be hitting us up for a wage increase a year or so later . Guess the lesson is like you say, to scout them better and then offer wages on their ability