I am trying to weld or braze a thin, hollow stainless steel coil to a large hollow stainless steel pipe.

Should I add guides along the large pipe to help the welder align the coil?

Will the welder bend the pipe (used for the coil) or does the coil need to be pre-formed?

Is there a way to increase the size of the weld between the two pipes (e.g. by adding a half-pipe guide along the surface of the large pipe)? I'm also trying to increase heat transfer between the pipes.