just making up some things for my car and i found it alot easyer to tig weld pipe when the pipe is standing up verticly, i get much nicer beads and can do the lot in 3 stop,starts.
Horizontal weld on a vertical pipe is commonly known as the 2G position, nice position to work in as you can usually rest the side of your torch hand on the lower pipe for more control, and visibility is usually good as well. As heat rises, the top pipe tends to soak up more of it, control heat by dipping filler at the top of the joint and gently washing it down to the lower edge with the torch. As with all tube and pipe joints, particularly small diameters, torch angle and arc length should be maintained as you progress around the joint, allowing the torch angle to fall back will cause loss of heat control. It's good that you are getting satisfactory results, kind of makes all the practice worthwhile!