Less is definitely more. Also try to avoid excess flux on the stanchions. One thing I do to make the solder a bit more workable is stir it with a little bit of the liquid flux (Supersafe brand, the blue stuff).
I have had some stanchions that fill with the flux but I've found that after painting & weathering, it's pretty hard to see unless you look really close. The main thing is to avoid making 'blobs'.
Ed