We didn't use a sphere effect when we did the film Quickening
, but you might want to take a look at the Mega Shield plugin
As b4uask30male mentioned, we did make a curved electric arc plugin
for the film, but I can't remember if they used that in Highlander I.
It seems like the quickening effects are different in every Highlander movie and series episode so we didn't try to stick to any specific effects. We made our quickening look the way we thought a quickening should look.
Good luck on your movie! I can't wait to see it!