A friend of mine and his dad built a tubular framed trike his welds were really neat i tried telling him that it looked nice with the welds untouched but they went to the extent of sanding them off and smoothed with filler it looks really nice as though the frame was all one piece if you know what I mean?
But that thing was defiantly a show piece. IMO your weldings plenty neat enough to be left alone. Especially as this is built to be used not shown! By time it's been hi build primed and painted they'll look plenty nice enough.