Sirs or Madams, I have no wish to get into a personal argument between folks on this forum .. but after, well, nearly 40 years flying, you might forgive me for throwing in a few observations ...
I have the pleasure of flying both a vintage light aircraft and pretty high performance jet airliner. I also have the responsibility of teaching said jet, both in the simulator and in the aircraft. Part of the sim syllabus is a demonstration of the downdraft potential under large Cbs, which can easily exceed the vertical performance of the aeroplane, and for your info, we can often squeeze 5-6000 ft per min. rate of climb from this aircraft if it's reasonably light. There are some scenarios where it is impossible to escape, despite being in clear air with the runway in sight. This is why my colleagues and I hold off when there are Cbs on the approach or the take-off path.
Call me old-fashioned, but personally, I would rather eat my own leg than deliberately fly my light aircraft under a Cb, wherever the MSA is.
Of course, you will get away with it for a very large percentage of the time. But one day................