Why not both?
Personally I prefer to set up playlists instead of just letting one song loop - gives you a bit of variety and lowers the chance that you'll end up hating the song you pick!

Given your general theme I could see a playlist involving the two songs you picked aswell as some of the following. I could image all of them as something a smith could listen to in the background - they're also all more on the "relaxing" side of things, which I feel might be better suited for an RP enviroment - not that I know much about that, but I image you dont want anything to distracting?

Anyways - here is my list for songs I would include in such a playlist:
Wailer and Waterwheels
Songs of Salt and Suffering
Navigator's Glory
Saltswept
Woe That is Madness

All have a certain rythm to them that makes me think of someone bashing a hammer on a piece of steel (or rather: they have a rythm that I could see being good for beating steel!) while being rather calm at the same time. Only exception is Woe That is Madness which is a bit more "aggressive", but still quite relaxing and suited for times when stuff in the forge gets really heated!