[Closed] Re-roasting medium roast coffee?

I bought a bag of medium roast arabica coffee beans from the duty free shop at Dar es Salaam. They are medium brown in colour, quite small and disappointingly mild in flavour as well as having a greenish nutty taste, which I guess is down to the low roast.

This morning I stuck one grind's worth in the top oven of the Aga, which is at about 240 degrees C, for ten minutes. They came out smoking, darker in colour and the favour was nearer to what I prefer.

Anybody else tried this? Do I go ahead and oven roast the lot? Or would it be better to do them by hand in a cast iron skillet on the hotplate?