Pet peeve.
Lightning doesn't have an "e" in it. Lightening is just something that pilots should do to maximize their chances at the bar on a Friday night.
In my PA31 days, I never had to penetrate a solid line of CBs, but I was fortunate to fly in an area where weather information wasn't scarce so flight planning to avoid it was relatively straight forward. I only recall the advice I was given by my more experienced colleagues in my early days. If you have to go through, fly as low as you safely can (respecting MEA); do your best to remain visual as along as possible; and try to pass the worst areas of precipitation and lightning on the upwind side.