Two pieces to 4.5" ?? I wonder if you are thinking of Dung Fu (5.7) to the left, which has a pretty decent chimney section. On White Lightning the usual recommendation seemed to be pro to 3", and that seemed to be adequate when I led it a couple weeks ago.
There is further info at mountainproject.com
You are right about the pro size. I also did the route with two 3 inch pieces. I usually recommend pro sizes larger than needed in order to encourage people to carry larger pieces, even if they end up not needing them. This seems a waste of energy, but I have found it to be a safe practice in the long run.
Most people seem to rappel after climbing this route. There are two options we've used in the past: (a) two 60m ropes from a two-bolt anchor a bit to the right, and (b) scramble down and right about 25 yards to two-bolt anchor, from which you can make a single-rope rap with a 60m.
Also, a minor point: there is no 'e' in 'Lightning' :)
Thank you, Rob. I already sent a PM to Johnny and asked him to add the extra descent info to my page. I am also going to add your descent info to the page myself. I will also make the necessary correction on the name.