Hi Jeff, I don't know about the dot shape but I seem to remember convergence problems on these sets being caused by a bad Selenium rectifier on the convergence board? Could be wrong, someone please correct me.
If you don't already have one there is a factory service manual for this model posted here:
http://www.vintagetvsets.com/schem/ctc7-small.pdf (right click and save or you'll be stuck for a while, 8 meg file)
It has all the info for setup.
Eric